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Lloyd’s Register Staff Association. 


TRANSACTIONS 


FOR 


SESSION — 1936-1937. 


LLOYD'S REGISTER OF SHIPPING, 
71, Fenchurch Street, 
London, E.C. 3. 


RULES. 


(1) The name of the Association shall be ‘“Lioyp’s Recisrer Srarr 


ASSOCIATION.” 


(2) The object of the Association is the advancement and dissemination of 
knowledge of present-day problems in Shipbuilding and Marine Engineering and 
Aircraft, by the preparation and discussion of communications on the various 


technical aspects of the subjects. 


(3) The membership shall consist of the Technical Officers of Lloyd’s Register 


of Shipping. 


(4) The members of the Association shall elect Members of Committee and 
a President and Honorary Secretary who, in consultation with the Committee, shall 
arrange the procedure of the Association. All Past-Presidents of the Association 


shall be members of Committee ez-officio. 


(5) The President, Honorary Secretary and Members of Committee shall 


retire annually and be eligible for re-election. 


(6) Papers contributed to the Association shall be for the information of 
Members, and shall be available for the Committee of Lloyd’s Register of 
Shipping, and the authors shall retain the right to subsequent publication, subject 


to the sanction of the Committee of Lloyd’s Register of Shipping. 


(7) Non-members may, at the discretion of the Committee, be invited to 


contribute papers to, or to discuss communications read before, the Association. 


(8) Meetings shall be held during the first week of each month from 


October to April inclusive, and/or at such times as the Association may hereafter 


decide. 


President 


Past Presidents 


Hon. Sec. 


J. G. Bucuanan. (Ge eAr 
O. 


R. J. L. Warp. (Ge 


Aberdeen - 
Barrow - 
Barry - - 
Belfast - - 
Bristol. - = 
Cardiff - - 
Dublin - - 
Falmouth - 


Glasgow = 


Greenock - 
Grimsby - 
Hartlepool — - 
Hull - - 
Leith - 

Liverpool - 
Manchester - 
Middlesbrough 


Newcastle 


Newport - 
Plymouth — - 
Sheffield 
Southampton - 
Sunderland 
Swansea = 


G. D. RITCHIE. 


W. Wart. 

J. CARNAGHAN. 

B. OC. Laws. 

A. A. A. CHALMERS. | 
W. Dennis Heck. 
W. ‘THOMSON. 

8S. F. Dorey. 

E. W. BiocksinGe. 


J. M. Murray, 71, Fenchurch Street. 


COMMITTEE—London : 


C. H. Srocxs. A. Urww. 


ibe EA YiounG. 


T. RicHARDSON. 
J. Hopason. 

D. M. CHapman. 
A. P. Scort. 

J. W. Gwynne. 
J. F. CAMPBELL. 
R. B. Grier. 

R. Morrrrr. 

yH. McQueen. 
|G. E. Murpoca. 
K. Ineuis. 

C. H. L. Preprres. 
C. A. Mitrar. 
W. Matcorm. 

J. Houston. 

H. C. Murray. 
A. SMELLIE. 

P. T. Brown. 
j\A. R. Rippe.. 
(J. H. Sowpen. 
D. MaAcFARLANE. 
A. T. THOMAS. 
W. Kimper. 

L. R. Horne. 
R. R. FLeeraaM. 
R. W. Cromarty. 


CONTENTS. 


SESSION 1936-1937. 


OcroBER 8 - - : - SPECIAL LECTURE. 


‘*The Development of Hull Form.” 


ee Onn, rsd., .5C- 
(National Physical Laboratory). 


Chairman: R. Marcr K. Turnsut, Esq. 


NOVEMBER 5 - = 2 - “Steering Gear.” 


G. BucHANAN. 


DECEMBER 3 - - - ‘*Hatchways.” 


J. G. BucHANAN. 


FREBRUARY 4. - - - - Seamless Steel Tubes.” 


G. T. CHAMPNESS. 


Marcu 4 - - - - “Manufacture, Survey and Testing of Electrical 
Equipment.” 


G. O. Watson. 


Marcu 24 - - - - ANNUAL BUSINESS MERTING. 


SPECIAL -LECTURE 


“THE DEVELOPMENT OF HULL 
FORM.” 


By J. F.C. CONN, Esq., B.Sc. (National Physical Laboratory). 


Chairman: R. Marcu K. Turnpuit, Esq. 


DELIVERED 8TH OCTOBER, 1936. 


1. Hisrorrcan INTRODUCTION. 


Men have built boats from prehistoric times, and a complete account of the development of hull 
form would necessarily include a history of ships and shipping. It is not proposed to explore the ancestry 
of ships in the present lecture, but a brief history of shipbuilding is, however, not only interesting but 
essential towards a sense of historical perspective and an appreciation of the progress achieved. It is 
intended, therefore, to summarise the origin and development of the modern ship before concentrating 
attention on the present state of knowledge and attainment. 


We can safely presume that primitive man was first borne upon the waters on a log or raft. The 
use of paddles would follow, and from raft to dug-out canoe represents the necessary and inevitable 
progress. From vessels of wood and skin structure the early shipwrights gained experience which 
doubtless led to ideas regarding the desirable and undesirable shapes of craft for use in river, lake or sea. 
An understanding of the properties of the lever led to oars, and, in due course, the first sails were set 
and wind was utilised for propulsion. Progress thereafter was achieved by trial and error, and the 
evolution of the full-rigged sailing ship was a slow process, extending over several hundreds of years, 
although that evolution was none the less a triumph of empiricism and craftmanship. Shipbuilding is 
an ancient industry, and only in recent times has it learned to rely on the preparation of designs and 
calculations. In the absence of sound theoretical principles progress is unavoidably slow. 


It is worthy of note that early investigators adopted faulty assumptions in their work on ship 
resistance. Both Newton and Euler accomplished little in this particular field, probably because they 
lacked the necessary modicum of practical knowledge. Experimenters were not unknown, however. 
Prince Henry the Navigator encouraged the building of new types of ships, and Portugal’s achievements 
in navigation may, in some measure, have been due to this enlightened policy of experiment and trial on 
actual vessels. Spasmodic and haphazard attempts to test ship forms were made by the Chevalier de 
Borda, by Romme, Chapman, Gore, and others in Italy, France, Sweden and England. Colonel Beaufoy 
conducted a long series of experiments in England from 1798 to 1798, but none of these efforts led to 
changes in the then art of shipbuilding. The days of applied science were not yet at hand. 


A revolution in shipbuilding occurred with the changes from sails to steam engines for propulsion, 
and from wood to iron for construction. The era following the Napoleonic wars witnessed the gradual 
suppression of the armed merchantman and the encouragement of speed in sea transport. Commerce 
flourished, goods were carried from one continent to another, and the demand for fast vessels led to the 
evolution of the clipper ships. Iron sailing ships became almost universal on account of the saving of 
weight in their hulls, and, later, steel ships came into existence for the same reason. The development 
of the steam engine on land was quickly followed by its adoption for marine propulsion. Paddles were 


gradually ousted by the screw propeller, invented apparently simultaneously by James Pettit Smith and 
John Ericsson in 1836. In 1839 the first propeller-driven ship was put into service. Steam navigation 
entered upon its rapid development in the middle of the last century, and it then became necessary, as 
ships increased in size and power, that the existing crude ideas regarding the desirable shapes and 
proportions of ships should give place to more accurate knowledge. 

In 1867 William Froude began towing models on the River Dart, and investigated the resistance of 
ships in a scientific manner. His remarkable abilities in both theory and experiment enabled striking 
progress to be made, and at last the testing of ship models was founded on a sound, scientific basis. 
Froude’s work was applied in practice by Scott-Russell, Edward Reed and William Denny. | It was thus 
a combination of scientists, experimenters and practical shipbuilders which enabled the science of ship 
model testing to be firmly established and, finally, applied in practical shipbuilding. The new knowledge 
was at first applied almost exclusively to warships, and only in the last two decades has attention been 
focussed on the problems of mercantile ships. A typical present day freighter can carry its deadweight 
on a fuel consumption one-half of that of the corresponding pre-war ship. This progress has resulted 
from improvements in hull form, propellers and machinery, but it is noteworthy that economic 


conditions have inspired and fostered the search for economy. Necessity has been the parent of technical 
development. 


In wood shipbuilding, the physical characteristics of the structural material imposed restrictions on 
both form and size. Further, the design of sailing ships demanded the provision of a greater degree of 
stability than is adequate for mechanically propelled ships, with hull forms adopted to give low resistance 
when the vessel is heeled to large angles under the action of wind pressure on the sails. These desiderata 
led to broad, deep ships of proportions which were adequate for the duties imposed, but entirely unsuitable 
for low resistance properties in mechanically propelled vessels running at higher average speeds. The 
legacy of the wooden sailing ship has lasted for many years, and influenced the form, proportions and 
structural design of the later steel vessels. 


2. THe Facrors AFFECTING DESIGN. 


A ship is a most complex engineering structure, and in common with the majority of engineering 
projects, its design represents a compromise between many conflicting requirements. 

The shipbuilder fulfils his contract with the shipowner by producing a vessel capable of carrying a 
stated deadweight with certain cubic capacity and accommodation, to attain a specified speed either on 
trial or on service. The dimensions are influenced by the cubic capacity required or, in other words, the 
type of ship, and by the length and height of superstructures, since the breadth will be governed by the 
provision of adequate stability. But the dimensions may be limited by the docking and harbour facilities 
available. Restricted draught may, in turn, necessitate the adoption of twin screws in cases where it Is 
impossible to develop the thrust required from a single propeller. The type of machinery affects the 
dimensions by governing the designer’s weights and allowances for fuel storage, seatings, etc. If also 
has a pronounced effect on the afterbody lines, dependent upon whether a single-screw or multi-screw 
arrangement is necessary, and here again in any one case (whether single or twin) the engine revolutions 
will affect the propeller dimensions and characteristics which, in turn, affect the shape of the hull. 

Whatever dimensions the designer may choose (or be compelled) to adopt, the vessel’s stability and 
trim in all working conditions must be satisfactory, the structural strength adequate for the trade in which 
the vessel is to be employed, and the requirements of the Board of Trade and other authorities must be 
complied with as regards freeboard, bulkhead subdivision, crew and passenger spaces, equipment, ete. 

It is exceedingly rare for a mercantile vessel to be designed primarily for speed, except for certain 
well defined and numerically minor classes of ship. In the vast majority of cases, the naval architect 
has to evolve the most efficient form on dimensions, proportions and fullness which may already have 
restricted the best result obtainable. The claims of deadweight, trim and stability rarely reinforce the 
requirements for low resistance and high propulsive efficiency. 

But the naval architect’s task is not quite so onerous as the above statements would suggest. He is 
relieved of the labour and complexity of strength calculations by the Classification Society. In addition, 
the optimum form of hull to suit the specified conditions can be evolved at an experimental tank. In 


many cases an efficient hull can be drawn out from the copious data already published by tank experi- 
menters. For the unusual types, not covered by the published results of methodical tests, experiments 
with a wax model will quickly supply an answer. The shipbuilder and engineer can check the relative 
merits of hulls, propellers, rudders and bossings by means of self-propelled tests in both smooth and rough 
water, Admiral Taylor has said that “the designer who is an optimist in choosing the efficiency of 
propulsion to be expected may be very pessimistic after the trial. The time for pessimism is when the 
powering is being done, not when the trial is being run.” But pessimism may lead to large margins for 
error and consequent over-powering of a ship hull. Tank tests afford a means of accurately estimating 
the power required. 


3. THe FUNDAMENTALS OF SHIP RESISTANCE, 


The resistance of a completely submerged body moving in an imperfect fluid may be divided into two 
component resistances, one due to pressure and the other due to frictional forces. When the body moves 
on the free surface of a liquid the pressure system produces a train of surface waves causing what is termed 
wave-making resistance. ‘The system of waves spreads out behind the body and the work done by the 
body against the waye resistance is converted into the kinetic energy of the wave system. Frictional and 
pressure resistances are expended in the momentum of eddies in the wake, the corresponding work done 
being dissipated in the kinetic energy of the eddies and subsequently transformed into heat. 


The components of ship resistance are gene rally considered as follows :— 


(a) The frictional resistance, which results from the rubbing of the water on the surface of 
the hull, is responsible for a large proportion of the total resistance, and is calculated to represent 
about 80 per cent. of the total for a slow speed merchant ship, and about 50 per cent. for a torpedo 
boat destroyer. This type of resistance leads to the formation of a frictional belt of slow-moving 
water which clings to the hull, increasing in thickness from forward to aft. Research has shown 
that this belt thickness, in non-divergent streams, depends mainly upon the roughness of the 
surface, its length and the form of the hall. 


(b) Eddy resistance, caused by any abrupt change of shape such as steep water line endings 
and under water fittings. The resistance from this cause is regarded as small except in the case 
of very full forms, where large unstable eddies may form and break up irregularly under the 
quarters, causing poor propulsive efficiency and erratic steering qualities. 

(c) Wave-making resistance results from the pressure system which exists around a moving 
hull. The pressure systems at each end generate their own groups of waves consisting partly of 
transverse waves with crests perpendicular to the direction of motion, and partly of divergent 
waves. The train of transverse waves emanating from the bow system is superimposed on the 
stern system and thus produces a fluctuating resistance depending upon the phase relation between 
the two systems. 

(d) Resistance due to wind acting upon the aboye-water portion of the hull. 

The difference between the total water resistance and that due to skin friction is termed the residuary 
resistance, the principal component of which is the resistance due to wave-making. Now the action of 
the waves is such as to distort the streamlines near the hull, and the form of the waves is in turn affected 
by the frictional wake, i.e., by the mass of water clinging to the hull which has been set in motion by the 
frictional resistance. Hence the frictional and wavemaking resistances of a ship are to some extent 
mutually dependent, although it is convenient in practice to neglect this interaction, which is known to 
be small, at least in the forebody. The augment of velocity in the potential flow, the pressure distribution 
and the influence of the waves on pressure and local velocities have been found to affect the frictional 
resistance by only a small amount. 


Those characteristics of a fluid which govern its motion are its weight or density, and its viscosity. 
The latter, usually specified by the coefficient of viscosity p, measures the frictional resistance exerted 
between adjacent layers of the moving fluid. In any comparison of fiuid flows, similarity of motion 


depends upon the quantity (coefficient of viscosity divided by the density) commonly written 7 and 


termed the “Kinematic Coefficient of Viscosity.” 


4 


Applying the method of dimensions to the case of the moving ship, we find : 


() Be fie) 
av =/ Jen 0) 


where R = resistance, 


S = wetted area (proportional to |*), 
p = mass density of the fluid, 
V = velocity of advance, 
f =a function, 
| = any linear dimension of the form, 
v = coefficient of kinematic viscosity, 
g = acceleration due to gravity. 
Neglecting wind resistance (which can be estimated separately, but is usually negligible in mode] 


tests), Froude assumed that the frictional and wave-making resistances were separable parts of the total 
resistance of any ship form. This is equivalent to writing :— 


(2) Ry =. Ry Ry 
pSV? psv? psv? 
where Ry = total resistance, 


Ry = frictional resistance, 
R,z = residuary resistance. 


He assumed that eddy-making resistance followed the same law as wave-making resistance and, 
further, that the frictional resistance of a ship form is the same as that of a thin plank on edge which 
has the same quality, length and area of wetted surface, and which moves at the same speed as the form, 


Equation (1) states that of the total resistance, the first part, wave-making, depends upon the ratio 


are ; AVL 
Ware and the second, frictional resistance, depends upon the ratio =" known as Reynold’s number. The 
dimensional relationship of Equation (1) shows that in the absence of liquids with kinematic viscosities 
very much smaller than those of water, it is impossible to make tests of a surface model under conditions 
which are completely similar, dynamically, to those of the full scale hull. 


E ee ‘ “speed”. 
The correponding speeds for model and ship will be those at which the ratio Flemath is the same 


for both, and at such speeds the wave pattern created by the model will be geometrically similar to that 
created by the ship. William Froude’s Law of Comparison for corresponding speeds, applicable only to 
the wave-making resistance, may be stated thus: “The resistance of similar ships are in the ratio of the 
cubes of their linear dimensions when their speeds are in the ratio of the square root of their 
dimensions.” 


But the frictional resistance does not obey this law, and in applying model results to the full scale, 
allowance must be made for the effect of kinematic viscosity. Froude accomplished this by measuring 
the frictional resistances of planks of various lengths and, by analysing the results so obtained, was able 
to extrapolate in order to arrive at estimates of the frictional resistance for the full size ship. 


Since Froude’s time a great amount of theoretical and experimental investigation has been lavished 
upon the subject of frictional resistance. The variations with form, degree of roughness, and temperature 
have been explored, but the estimation of the full scale frictional resistance is still a matter for final 
verification and proof. 


Justification for neglecting the interaction of the component resistances and treating them separately 
is furnished by the close agreement between the results of experiments on models and on ships, where 
the proportion of frictional to total resistance differs greatly, 


4. TANK EXPERIMENTS. 


An experimental tank consists primarily of a long waterway spanned by a travelling carriage from which 
models can be towed. The length of the waterway is governed by the speed desired ; distance is required 
for acceleration, for a suttic iently long run at steady speed, and for retardation. The breadth and depth 
are regulated mainly by the size of models to be used, as the waterway must be sufficiently broad and 
deep to obviate any possiblity of interference between model, side walls and bottom. Shallow docks are 
usually provided at the starting end for loading and trimming models. Arrangements for breaking up 
and damping out the waves generated by models during experiments are fitted in the form either of a 
shelving beach at the far end or trough-like cavities in the side walls near the water level. 


The travelling carriage spans the width of the tank and is carried on four unflanged wheels running 
on rails laid on the centres of the concrete walls. The carriage is constrained to move in a straight 
course by guide rollers bearing on the vertical planed faces of one of the rails. The carriage wheels 
are coupled together in pairs and driven by D.C. reverse compounded motors; current is supplied to the 
latter by trolley poles on the carriage, which make contact with conductor rails fitted either on the side 
wall or roof of the building enclosing the tank. Constancy of carriage speed is essential and for this 
reason special precautions are taken to ensure a steady voltage supply. 


The model hulls are of wax, cast in china-clay moulds shaped by hand, cut to shape in a special 
machine which cuts out closely spaced waterlines, finished by hand-scraping to a smooth, polished surface, 
and ballasted with iron weights to float at the required displacement and trim in the fresh water of the 
tank. 


The composition of the wax is 90 per cent paraffin, 2 per cent beeswax, and 8 per cent stearine, 
melting at 125° Fahrenheit. The stearine gives hardness and the material is sufficiently hard without 
being brittle. Wax models are thus quickly and cheaply made. They have the outstanding advantage 
of being easily re-cut and modified in shape so that the effect of modifications in form design are quickly 
investigated. The finished wax model, loaded and trimmed as desired, is towed underneath the travelling 

varriage over a range of speeds which extends well above the service speed of the ship. The model 
resistance is measured on a dynamometer while records are taken of the velocity. From these data the 
tow-rope or effective horse-power values are calculated, the resistance being corrected for the relative 
densities of fresh and salt water. 


When a shipbuilder subinits a set of lines for testing, a model is made to these lines on a suitable 
scale. The model is then towed as described above. From the measured results for resistance and speed 
the value of the resistance constant C is calculated and plotted to a base of the speed constant P. 
Examination of the curve shows whether the form is satisfactory for the designed speed, subject to the 
specified conditions. If unsatisfactory, modified forms can be drawn and the model re-tested until a 
good result is obtained. The C curves are corrected for the effect of scale on the skin frictional 
resistance and to a standard temperature of 59° Fahrenheit, and curves of effective horse power are then 
computed. 

The problem of resistance, however, is inter-related with that of propulsion, and to obtain the most 
efficient combination of hull and propeller it is advisable to test the two in combination. Model 
propellers are constructed in a fusible metal alloy of 20 per cent lead, 70 per cent tin and 10 per cent 
bismuth. Rudder, fin, bossings and other appendages are constructed in metal or wood, depending upon 
the type and size, ‘and the model is then self- propelled, i.e., propelled by its own propellers, the latter 
being driven through suitable gearing by a small shunt-wound motor fitted within the model. A 
torsionmeter, thrustmeter and revolution counter are fitted on each shaft. During the experiments the 
model is towed in the usual way from the resistance dynamometer, and the propeller revolutions are 
adjusted until the resistance recorded shows that the model is under-, over-, or exactly self-propelled. In 
this way the exact point of self-propulsion is obtained graphically, and the propeller characteristics are 
determined over a range of slip corresponding, for example, to a range of resistance at one particular 
speed—such as would be caused by fouling of the hull or rough weather. 


Other experiments can be made in the tank, of which the commonest types are rolling, steering and 
streamline explorations. In the latter, the flow over any required area can be mapped out by observing 
the positions taken up by small vanes on the bull surface. Such tests are particularly useful for giving 


the optimum shapes and positions of bilge keels and shaft bossings. The measurement of wave profiles 
is easily effected, and of paramount importance in the case of paddle steamers, where the paddles must 
be located in the hull to operate at the designed immersion. Resistance and propulsion tests can also be 
carried out in rough water, waves of the requisite height and length being generated by a wave-making 
machine mounted at the far end of the tank. 


5. ‘Tue Erricienr Hunn Form. 

The qualities of an efficient hull form may be enumerated as follows :— 

(a) Low resistance, coupled with high propulsive efficiency. It must be emphasized that the 
hull giving the lowest tow rope or effective horse power at any given speed will not necessarily 
require the minimum shaft horse power at that speed. It is possible in many cases to produce 
forms of very low resistance which, owing to defects in afterbody shape, impede the inflow to the 
propellers and thus give a low propulsive efficiency. In this matter, again, compromise is 
inevitable. 

(>) Ability to maintain speed at sea with the minimum increase in shaft horse power over 
the shaft horse power required for the same speed in calm water. This demands good design in 
hull and propeller, singly and as a combination, 

(c) Good steering and manceuvring qualities, where form of hull again has its effect. 

It is impossible to calculate ab initio a vessel’s resistance to motion. Estimates of power must be 
based either on results obtained on actual ships, or from model tests. Since full-scale towing tests are 
necessarily limited in extent, difficult to execute and prohibitively expensive, the extent of our present 
knowledge is entirely due to research work done in experimental tanks. Future progress must, so far as 
can be seen at present, derive from the same sources, 


Resistance to motion, height of wave profiles, etc., can be calculated for certain forms under certain 
simplifying assumptions. A considerable amount of mathematical work on the wave-making resistance 
of ships has been, and is being, done. The mathematical difficulties are acute, the arithmetical computa- 
tion 1s laborious, but agreement between calculated and experimental results is remarkably good. 
Mathematical analysis has been of great utility and of undoubted practical value. Wave-making resistance 
is the source of many unique phenomena, among which the problem of interference between bow and stern 
Wave systems is perhaps the most interesting and the most troublesome in practice. 

It as been found experimentally (and confirmed theoretically) that the product prismatic co-efficient 
multiplied by length (or volume of displacement divided by midship area) can be regarded as a “ wave- 
making length” for any given ship form—a factor which can be evaluated in the early stages of design. 
It has also been found that humps in the resistance curve occur when P = 555, °663, °895 and 1°). 
These detine the speeds at which maximum wave-making may occur. Minimum wave-making occurs 

2 , V 
When P = 612, °757, and 1°155, when P = x ‘746 
J pl 
V = speed in knots, 
p = prismatic coetticient, 
L, = length in feet. 


Hence it is possible to avoid excessive wave-making resistance by suitable adjustment of the 
dimensions in the early stages of design. In any given case, improvement of the hull is effected by 
altering the form in such a way that the modification of the pressure system reduces the wave-making. 
It has already heen stated that the system of waves is formed by the pressure system which results from 
the vessel’s motion through the water. The pressure distribution on the hull, and the configuration of 
the wave system are thus mutually dependent. The longitudinal positions of the bow crest and hollow 
are largely regulated by the position of the excess positive pressure near the bow, together with the 
negative pressure at the shoulder of the entrance. The distribution of these pressures varies with the 
shape of the hull. It also varies, for any one hull, with the speed. Fig. 1 shows the wave profile and 
distribution of pressure on a 39°5 ft, pinnace. The figure has been replotted from a paper by Yokata 


and others, given at the World Engineering Congress in 1929. The pressure measurements were 
obtained by a large number of pitot tubes fitted to the hull surface. Inspection of the diagram shows 
the general similarity in form of wave profile and pressure distribution up to a considerable depth below 
the water level. Humps and hollows in the wave profile are reflected by similar features in the pressure 
curves. If the elevation of the water at the bow is reduced, the resistance also decreases. This shows 
how resistance is diminished by a bow modification which reduces the height of the bow wave. 


6. Tue DirreRENT SHip TYPES AND THEIR RESISTANCES. 


The resistance characteristics of several ship types are illustrated in Fig. 2, which shows the C curves 
for several vessels brought to a standard length of 400 ft. for purposes of comparison. The fast vessels, 
notably the destroyer and cross-channel steamer, are remarkable for excessive wave-making, displayed in 
the large values of © and the steepness of the curves. Each type has its own peculiarities, and general 
statements regarding resistance properties can be made only at the expense of accuracy. 


Generally, for a given displacement and length, assuming that the shape is fair and no serious eddy- 
making occurs, the resistance of a ship at any speed is largely determined by 


(a) The shape of the curve of cross-sectional areas—which determines the prismatic coefficient 
and the longitudinal centre of buoyancy. 


(6) The extreme beam. 
(c) The form of the loadwater line, particularly in the forebody. 


Considering the general case of an arbitrary hull form, the size or displacement is a primary factor. 
Secondly, proportions affect the resistance. The most important dimension is the length used for a given 
displacement. In this sense length is a major factor, while beam and draught are comparatively minor 
factors. Length is most valuable for reducing the wave-making resistance; in high speed ships, where 
the wave-making resistance is a large proportion of the total resistance, the latter is most easily reduced 
by increasing the length, although the skin frictional resistance is increased thereby. 


Thirdly, the nature of the ends, whether fine or full, affects the resistance, and this form characteristic 
may conveniently be assessed by the prismatic coefficient. This factor can exercise a vital effect on the 


resistance. For moderate speeds, i.e., TS 0:8, low resistance is obtained by adopting a large midship 
4 
V 


area and fine ends. About YL= 0°95 there is an indeterminate region where the prismatic coefficient 
i 
] 
has comparatively little effect. At the higher speeds, Ta Pag 1°3, it is advantageous to use prismatic 
4 
coefficients as high as 0°66 by reducing the midship area and adopting comparatively full ends. At the 
highest speeds, length, beam and displacement are the main factors affecting the resistance of, for example, 
a high speed motor boat ; form of hull becomes relatively unimportant, except as regards propulsion. 


The forebody has a much greater influence on resistance than the afterbody. Experiments have 
shown that radical variations in the shape of afterbody sections have only a minor effect upon the hull 
resistance. ‘The maximum possible change in resistance which can be caused by reasonable variation of 
the afterbody sections in a cargo ship does not exceed 10 per cent. of the total resistance. On the other 
hand, the afterbody has a vital effect upon propulsive efficiency and should be designed to give good 
propulsive qualities rather than low resistance qualities, since these desiderata may be conflicting. 


Fig. 3 (replotted from ‘Systematic Experiments on Cargo Ship Forms,” by A. Shigemitsu, Journal 
of the Society of Naval Architects, Japan, Vol. 46, 1930) shows three different designs of afterbody for a 
cargo steamer, varying from V-shaped sections in Model 102 to U-shaped sections in Model 103, with 
Model 101 having sections intermediate in form between the two extremes. 


Fie. 4 gives the © curves for these three models. The V-shaped afterbody of Model 102 gives the 
lowest resistance. The club footing adopted in Models 101 and 103 causes greater resistance, but gives a 
more uniform wake over the propeller disc, which conduces to more efficient propeller action. 


8 


Fig. 5 shows the effect of draught upon a vessel of this type. It is noteworthy that decrease of 
drank ratio gives a better performance, shown by the lower values of C. In other words, for relatively 
slow-speed cargo vessels the © value at any given speed increases rapidly with decrease in displacement. 
For such vessels the skin frictional resistance is the largest component of the total resistance and as 
draught increases there is more displacement per unit of wetted surface, hence a lower resistance. 


Fig. 6 (redrawn from “Systematic Model Experiments on Intermediate Liner Forms,” by 
M. Yamagata, Journal of the Society of Naval Architects, Japan, Vol. 50, 1932), shows three different 
designs of afterbody for an intermediate liner, and Fig. 7 gives the C curves. Here again the V-shaped 
afterbody sections show to advantage at low speeds, but lose this superiority at higher speeds. Fig. 8 
gives the results of tests on one of these models at four dispacements. It will be noted that to obtain a 
lower C value at higher speeds decrease in displacement on a given length effects a marked improvement, 
and this fact holds true for all fast vessels. 


Conservation of energy is universal in nature and the flow of water along a hull will be in the easiest 
and shortest path. For this reason, very broad vessels should be given the easiest possible buttock lines. 
With the same reasoning, therefore, very deep vessels should have waterlines of gentle curvature. It has 
been observed in tests on struts, airship forms and various solids of revolution, that eddies tend to form 
when water flows along a surface whose inclination to the line of flow exceeds 18 to 20 degrees. For this 
reason, particular attention should be paid to waterline and buttock slopes in the afterbody. Baker has 
given a rule that the length of run should exceed a length given by 4°1 x (midship area). Waterlines 
in the afterbody should be drawn so as to have the smallest possible slopes and it is in this connection that 
a cruiser stern becomes profitable. Greater length on the waterline enables the afterbody to be drawn 
out, and easier slopes (of both waterlines and buttocks) obtained thereby. Hence it is that the adoption 
of a cruiser stern may give an improvement up to 5 per cent. in resistance. 


The design of the forebody in low-speed ships affords greater latitude, and forms widely different in 
shape can be designed to have the same resistance. The alternatives in the case of the 400 feet., 10 knot 
cargo steamer of average breadth, are, roughly :— 


(a) A full bow angle of 35° to 40° inclination to the middle line, coupled with pronounced 
V-shaped transverse sections. 


(6) A finer bow angle of 30° to 35° with U-shaped transverse sections. 


In high speed vessels there can be no departure from a fine bow angle if wave-making resistance is 
to be small. The prismatic coefficient gives an indication of the nature of the ends, whether fine or full. 
A guide as to the comparative fullness of the forward and after bodies is given by the longitudinal centre 
of buoyancy. For full, slow-speed vessels this should be well forward of amidships, as far as 2 per cent 
of the length. With finer forms and higher speeds the longitudinal centre of buoyancy should move aft 
and, in liner forms, should be located about 1 per cent of the length abaft midships. 


The resistance of appendages can be reduced to the minimum values by setting them in the ideal 
positions as found by stream flow explorations. Bilge keels, for example, should be placed so as to cause 
the least disturbance to the flow in conditions which represent the average working draught. When bilge 
keels and bossings are located in this way, and the bossing ends are properly tapered, the appendage 
resistance should be no greater than the skin frictional resistance of these surfaces. 


Eddy see is reduced to a minimum by the fitting of fins on rudder posts, the tapering of 
propeller posts and the streamlining of rudders. 


OTHER FacrorRS AFFECTING THE RESISTANCE. 


1, SHaLLow Warer.—The foregoing discussion holds good only for vessels in deep water. 
Generally, the resistance in shoal water is greater than in deep water at moderate speeds, but at higher 
speeds the reverse holds true. The alteration in resistance is due to shallow water causing a two- 
dimensional flow around the hull, whereas in deep water the flow is three-dimensional, with smaller 
pressures than in the former case. In shallow water the larger pressures cause larger waves, and the 
latter are of greater length than waves of the same height in deep water. The higher velocities over 


the hull surface also tend to cause greater frictional resistance in shallow water, and conditions are much 
more favourable for eddy making. For ordinary cargo vessels there will be no abnormal increase in 
resistance unless the speed is greater than that given by 


(speed in knots)? = 8°0 x depth of water. 
For finer, faster vessels the corresponding formula is 
(speed in knots)? = 5:3 x depth of water. 


Our knowledge of the effect of shallow water has been gained mainly from tests in experimental 
tanks, where a false bottom can be fitted in the tank to simulate the full-scale conditions. 


2. Rouen Warer.—Since the inception of model tests, efforts have been made to determine the 
effect of rough water on resistance, and to find those qualities of form which are conducive to good 
behaviour in a seaway. An important problem was to determine whether the optimum model, judged by 
smooth water performance, maintained its efficiency in rough water. R. E. Froude concluded that results 
obtained in smooth water held good for a regular seaway, so far as the relative merits of straight or hollow 
waterlines were concerned. This conclusion remains valid, and comparison of other model tests with 
voyage results have indicated certain form characteristics which are to be avoided. Such features as flat 
areas under the forefoot, for example, and others which generally lead to pounding damage, show their 
deficiencies in model tests. Where pitching and heaving are concerned the weight distribution over the 
vessel’s length may have a more important effect than form; smallness of the longitudinal radius of 
gyration should be aimed at, although with short wave lengths a longer natural period may be used. 
Mr. Kent has found from model experiments that with identical wave trains, speed and principal 
dimensions, fullness has no material effect on the amplitudes of heaving and pitching. It was found, 
however, that in the region of resonance, fine models actually heaved to a greater extent than full ones. 


7. Progress ATTAINED AND FuTURE DEVELOPMENTS. 


Form design has developed from the empiricism of sailing ship days to the new empiricism of model 
tests. In the former case the efforts towards improvement were spasmodic and unco-ordinated. In the 
latter, experiment is guided by sound knowledge of the fundamental principles towards well-defined aims. 
The optimum hull to suit given conditions has ceased to be a matter of conjecture and become a problem 
capable of exact solution by experiment with models and investigation of ship performance, The analysis 
of service results is essential if model and full-scale performances are to be correlated, e.g., ships are no 
longer built with the high block coefficients which were so popular in the earlier days of steel shipbuilding. 
Sea experience showed that excessive fullness leads to bad performance in rough weather at sea. 


There can be no finality in the development of ship forms. New designs, patented and unpatented, 
continue to be produced, and new types of machinery will demand new afterbody designs, as in the case 
of the change from reciprocating to turbine engines. The present use of high-speed oil engines, with 
fast-running propellers, is a typical example of engineering progress affecting the form of hulls and 
propellers. 


Development is continuous in human affairs and one may speculate rather than prophesy regarding 
future developments. Even if it were possible to eliminate wave-making resistance—and although experi- 
menters are continually seeking to reduce it, perhaps not one of them entertains such a hope—skin 
friction remains the main component of the resistance and represents about 80 per cent. of the total in 
the majority of ships. This resistance can be reduced in either of two ways. Firstly, since it is directly 
proportional to the wetted surface, which depends mainly on the transverse dimensions of the hull, the 
wetted area should be reduced to a minimum. It can be shown that, to a close degree of approximation, 
minimum wetted surface will be obtained when 


Breadth _ 17 
Draught — block coefficient 


This fact should be utilised in design when there are no limitations on dimensions, and a suitable 
block coefficient has been chosen. 


10 


Secondly, with a given surface, the resistance can be reduced by making the area as smooth, clean 
and free from obstructions as possible. ‘The advantages of good paint, applied to a dry hull and allowed 
to set hard, need no emphasis. But there are many different kinds of roughnesses on a ship’s hull 
produced by seams, butts, rivets and even by layers of paint. Fouling increases roughness, and hence the 
resistance, by extraordinarily large amounts. ‘Tests have shown that the elimination of seams and butts 
in the forebody may decrease the frictional resistance by as much as 10 per cent. in a cargo vessel. It is 
reasonable to hope that the advent of welding and, later, some form of rustless steel, may allow hull 
surfaces of such smoothnesss that the resistance will be appreciably reduced. 


Tests carried out in the U.S.A. and in Germany on plates immersed in sea water have shown that the 
colour of paint effects the fouling properties. On a green paint, in which the colour corresponded to a 
certain wave length, the fouling was only one-sixth of that on the usual red paint. Here is a matter in 
which the marine superintendent may make his own experiments. 


In still air the wind resistance of a vessel’s hull and upper works represents about 2 per cent. of the 
total resistance. By “streamlining” bridges, funnels and erections the ahead resistance due to wind can 
be reduced by 30 per cent. The corresponding saving in speed varies from a quarter knot for a high 
speed ship meeting a 20 knot wind, to 1 knot for a low speed ship meeting a 40 knot wind. 

When treating so large a subject in so small a compass, condensation is necessary, and if the Author’s 
account of the development of hull form is very much abridged, it is hoped that the interest and importance 
of the subject have not suffered thereby. 


MIDSHIP SECTION 


, SHOWING LEVELS AT 
WHICH PRESSURES 
WERE MEASURED 


‘75 


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WAVE PROFILE IN DEEP 
WATER AT VAT - 0-82 


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Wave Coyxrovr ano Lonerreprxan Pressure Distripution on Hubb. 39°) Fr. Prinnace at 5°14 Ks. 


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For THE STANDARO 400 SHIP IN EACH CASE 


THE VALUES GIVEN ARE 


©: more 
® . YY «2746 
VPL 


wrere EHP = EFFECTIVE HORSE POWER 
Q * DISPLACEMENT IN TONS 
Vs SPEED IN KNOTS 

P * PRISMATIC COEFFICIENT 
L 


* LENGTH WN FEET 


12 3 14 1S 16 17 18 


19 


TYPICAL CARGO SHIP__ AFTERBODY VARIATIONS 


SNOILVIAVA ACGOEAAL AY 


4O 1934453 ONIMOHS § S3AxNDO) 


TYPICAL CARGO SHIP 
EFFECT OF CHANGES IN DRAUGHT 


INTERMEDIATE LINER 2 AFTERBODY VARIATIONS 


© CURVES SHOWING EFFECT OF 
‘3 AFTERBODY VARIATIONS ji 


[ 


INTERMEDIATE _ LINER 
EFFECT OF CHANGES IN DRAUGHT 


| 2060 | 7625 
' 1857 | 6780 
t 


1653 | 5925 


STEERING GEAR. 


By G. BocHANAN. 


Reap 12TH Novemper, 1936. 


STEERING GEARS. 


The recent enquiries into the loss of various ships, in which mention was made of damage to 
steering gears, have drawn particular attention to this portion of the equipment of merchant vessels. 


While the initial damage itself may be of a more or less trivial nature, the subsequent damage which 
may result due to either collision, grounding, or other cause because of a defect in the gear, makes it of 
paramount importance. All passenger ships and the majority of new ocean-going cargo ships are fitted 
with a type of gear working directly on the quadrant, either electro-hydraulic or steam driven, dependent 
to a large extent on the type of main propulsive machinery installed. The choice of the method of 
steering is the prerogative of the owners and depends on their previous experience, and, while it is 
generally considered that a steering gear working directly at the rudder head causes less trouble and the 
cost of upkeep is lower, the smaller initial cost of the rod and chain gear will always be an incentive to 
owners to instal it. 


It is proposed to divide this paper into three main parts to deal with each of the principal steering 
gear arrangements :— 


(1) Steam gear situated amidships controlled by rods and bevel wheels, the power being 
transmitted to the quadrant by means of chains and rods, 

(2) Steam gear coupled direct to the rudder head quadrant and controlled by telemotor cr 
rods and bevel wheels. 


(3)  Klectro-hydraulic and steam-hydraulie gear with telemoter control. 


Rob AND CHAIN STEERING GEARS. 


In medium-sized cargo ships and in smaller ships of all kinds, the steam steering gear situated 
amidships and controlled from the bridge by means of shafting still retains its popularity with owners, 
although it is perhaps being superseded gradually by later designs situated at the rudder head. In all 
probability the steering engine in the engine room receives more attention in small vessels with a reduced 
engine room staff than would be the case if it was situated at the aft end of the ship. 


Due to the enquiries mentioned previously, some severe criticism was levelled at the rod and chain 
gear as the majority of the vessels lost were fitted with this arrangement. The fact should not be lost 
sight of that the majority of the existing tramp steamers up to 5,000 tons deadweight and some of the 
older ships up to 8,000 tons deadweight are fitted with this method of steering and that the percentage 
of defects is relatively small. 


It is generally admitted that the rod and chain gear is reliable when properly designed and fitted, 
provided it is kept in thorough repair and efficiently maintained, although due to its exposed position and 
the length over which the movement is transmitted, it is more liable to damage due to wear and tear and 
heavy weather than other types of gear. 


To give some idea of the vulnerability of the different parts of the gear, it may be well to quote from 
the Steering Gear Committee’s report. Out of 334 cases of damage reported from Feb. 1926 to 
Dec. 1935, 219 related to rod and chain gear and these were split up into the following percentages :— 


Per cent, 


Chains and shackles oes Be ae ae er eG 
Rods dss x. see Sat Ri aS a: 6 
Spring buffers... or f vee ame Hach J aD, 
Warwick screws ... Ae rep ae oe mae 5 
Fairlead pins... ay apr fos a re 6 
Deck attachment and frames of fairleads a fe 
Quadrants, stocks and tillers... “ea ae ae 6 
Chain drums, gears, shafts a are ay 12 
Miscellaneous... wae ae eS 14 


From the figures given it will be seen that the greatest source of failure is the chain itself and 
following this, the spring buffer. 


With regard to the figure of 219 cases of damage to rod and chain gears in ten years which have 
heen investigated by the Committee, it must be borne in mind that these include both classed and 
unclassed ships. 


To obtain a correct perspective of the problem, it should be remembered that out of 10,000 
casualties reported in the casualty lists in one year, only 70 or 0-7 per cent were in any way related to 
steering gears, and of these, half were of such a trivial nature as to be negligible. This figure again 
includes both classed and unclassedships. 


There are several types of steering gear which may be fitted amidships, depending on the 
arrangement and space available. Probably the best, from the point of view of a suitable and easy lead 
of chains to the quadrant, is the horizontal steam engine on a raised bedplate, driving a main shaft with 
extended ends, having bearings at the house side, and the drums fitted between the house and a pedestal 
hearing on the extreme ends of the shaft. From the drums the chains can be led along the sides of the 
hatchways to the quadrant, thus obviating the right-angle bend at the hatch side or ship’s side which is 
introduced in other arrangements. 


Where the space is not available for this type, a single drum may be placed outside the house on the 
centre line of the ship, in the fore and aft direction, with the shaft carried through the house end 
to the engine. 


If the space is still more restricted the drum may be fitted to the main shaft under the engine and 
between the legs of the pedestal and the chains carried through the house side. In an engine of this 
type, the sides of the engine casing are no longer weathertight and a steel bulkhead would be required 
between the steering gear space and the engine room, instead of the low coaming which is the 
usual arrangement. 


Other alternative arrangements, including a vertical engine fitted to the aft bulkhead with a 
horizontal shaft lying fore and aft, are available but rather uncommon. 


In general the engine is a two-cylinder horizontal steam engine on a raised bed plate, supported by 
cast iron columns and capable of starting in either direction from any position. The power is transmitted 
from the engine through a worm, gearing with a worm wheel keyed to the main shaft, at the ends 
of which the barrels are fitted. The valves are of the piston type and an economic valve may or may not 
be provided. he effect of fitting an economic valve is to shut off the passage of steam when the engine 
is not working, which greatly reduces the steam consumption of the engine. The engine is usually controlled 
by rods and bevel wheels and universal joints from the steering standard on the bridge and an automatic 
hunting gear is incorporated in the engine. Rollers are usually provided to guide the chains correctly on 
to the chain barrels, 


.-+The only regulation as regards the power of the engine is that it must be capable of putting the 
rudder from hardoyer to hardover in 30 seconds when the vessel is going at full speed. Due to the power 


taken up by the rod and chain gear in overcoming friction and the tosses inherent in a power tranmission 
of this kind, it is estimated that a midship engine must be 25 per cent larger than the engine required 
by a gear at the aft end, transmitting its power “direct to the rudder. 


For conveying the movements of the steering engine to the quadrant, in most cases the chains and 
rods are led either along the hatch side or along the ship” s side in the waterway. The better method is to 
carry the lead along the. hatchway, as, due to the curvature of the deck, the rods carried along the bulwark 
are liable to jam. The drawback to the hatchway lead is that the rods are generally boxed in with steam 
pipes led to the winches and may not get the attention which is due to them. 


When a deck cargo of timber is carried, the freeboard regulations require that the steering 
gear leads are always accessible, and, in this case, the chains and rods should be led along the ship’s side, 
as the cargo can be stowed in such a manner that they can be attended to much more easily than would 
be the case in the alternative arrangement. It is suggested that similar precautions with regard 
to stowage should be taken with any kind of deck ¢ argo, and that the rod and chain gear is partic ularly 
liable to “damage due to this cargo shifting. On a number of occasions the steering gear has been put 
out of action, due to a piece of deck cargo lodging in the chains or below the rods and the gear has been 
jammed and found impossible to move. 


In some vessels with poop, bridge and forecastle erections, the steering engine is on the bridge deck, 
and the steering rods are carried over the well from the bridge to the poop on supports level with the 
superstructure deck. This is an ar rangement which is very liable to damage due to the shifting of deck 

cargo, as the supports get twisted and the lead is put out of alignment. Also the rods and supports are 

removed in way of the hate shways when cargo is being loaded and unloaded, and this may lead to 
trouble. In a case of this kind the steering chains and rods should, if possible, be carried down into the 
well, alongside the hatchways and up to the poop deck or a better arrangement is to fit the quadrant 
inside the poop and carry the rods through the poop front bulkhead. 


It has been suggested in some quarters, that the use of wire rope in lieu of chains and rods would go 
a long way to reducing the number of breakages as, due to its resilience, it would not suffer to the same 
extent from sudden loads. While this is probably correct, the stretch of a wire under these conditions 
would be such that it would be difficult to keep it taut, and the renewals due to wear would be much 
greater than with the chains and rods. although, in all probability, the signs of wear would be easier to 
discover. During the war, some of the standard ships were equipped “with a wire lead, carried on 
supports between the poop and bridge, but it is not known if they were exceptionally successful. In any 
event, it is not thought that this arrangement would be suitable for a vessel carrying a deck cargo. 


STEERING CHAINS. 
In Lloyd’s Rules, the diameter of the chains, and also of the equivalent rods, are given for each 
diameter of rudder head in association with a definite radius of quadrant. If this radius is varied from 


that contemplated by the Rules, the chains and rods require to be increased or decreased to give 
equivalent strength. 


The practice of the steering gear makers is, apparently, to supply an engine which will give a 
maximum stress in the rudder stock of about 5 tons per sq. in., and in order to produce this assumed 
stress, the working load on the chains is approximately equal to one half the proof load, giving a factor of 
safety of 4. On the other hand, within the range of stocks which is under consideration, namely 6 ins. 
to 12 ins. for speeds up to 12 knots , the working ‘load on the chains based on the usually accepted rudder 
formula is well below this ratio. Taking the force on the rudder at 2 AV? lbs. (where A is the area of the 
rudder and V is the speed in knots) the pull in the chains required to turn the rudder can be found. 


On this basis, the factor of safety, would vary from about 5 for the smaller diameters to 6°5 for the 
larger diameters, using the existing table for a 10 knot ship, and would be still further increased 
for speeds below the minimum of 10 knots. 


These factors of safety are for a static load on the rudder and do not take into account the force due 
to a blow by a wave. As this force does not vary as the square of the speed, it appears to be correct that 
the factor of safety of the vessels of lower speeds should be higher than those which have had the rudder 
stocks and chains already increased due to the higher speeds. 


4 


In respect of this shock, it should not be forgotten that spring buffers are introduced to eliminate, 
as far as possible, this increased stress, and if they are of a suitable size in relation to the chain they will 
carry out this purpose effectively. 


Also, both the diameter of the rudder stocks and the size of chains are based on the maximum speed 
of the vessel, a speed which is rarely obtained in p ractice as it is both uneconomical and only achieved 
_under the very best conditions, and further, that it is a universal practice to reduce speed in any sort of 
heavy weather. 


It will be noted that the factors of safety given are for speeds of below 12 knots. Those for speeds 
of above this figure are reduced slightly, but, at the same time, very few vessels of above this speed are 
fitted with a steering gear of this type. 


With regard to the dimensions of the links of the chain, the overall dimensions appear to vary 
considerably, depending on the practice of the makers. 


According to the British Standards Specifications for short link crane chains, and also the Home 
Office requirements for the same type of chain, the outside dimensions of the short links are—length 
44, times the diameter of the material and width 3} times the diameter of the material. The following 
table gives the approximate dimensions of links made by a well-known maker of chains and the ratios of 
length and width of the chain are slightly higher than those given above. 


Inches. Inches. Inches. | Inches. Inches. | Inches. 
Diameter of material... 4 | 3 | 1 i} 1g 1} 
Outside length of link ... 23 34 43 54 64 wh 
Outside width of link... 113 26 345 | 43; | 43 5} 


‘The dimensions of the links when finished are about + { in. on these figures but they may be taken 
as average figures. 


To give some idea of the variation which is experienced, some 1} in. diameter chain measures 
7} ins. x 4,%¢ ins. over the link. 


In the Rules, in addition to the diameters of chains and rods, the diameters of leading block sheaves 
and pins are given, the former being sixteen and the latter twice the diameter of the chain. No rules are 
laid down for buffer springs, rod connections, shackles, Warwick screws or the connection of leading block 
fairleads to the deck, although they are all expected to be reasonably in accordance with the strength of 
the chain. 


The Steering Gear Committee have now raised the question of rules being introduced with which 
these subsidiary parts of the gear would comply in order to maintain the same strength throughout the 
installation, and in their second report have published proposed sizes for the different items in relation to 
the size of the chain. They have also advocated that the different parts be tested to the proof load 
of the chain. 


BUFFER SPRINGS. 

These are required to be fitted to all power-operated steering gears to absorb the shock of heavy 
blows by the sea on the rudder. 

In general, these springs are of two types, namely, those encased in oil-fitted cylinders and those 
which are open to the air. The advantage of springs enclosed in oil baths is that they are protected from 
the corrosive action of air and sea-water and are always efficiently lubricated and also that the cushioning 
effect of the oil allows a decrease in the size of the spring corresponding to a given diameter of chain, 


D 


The following particulars are taken from the catalogue of a well-known firm of spring manufacturers 
and represent first class present day practice. 


ENcLosED IN O1n-FiLED CYLINDERS. 


Chain Square Section | aah Outside : : 
Tse ceaell| of Spring. ‘Length of Spring. Dismeur Number of Coils. 
Inches. Inches. Inches. Inches. 
4 3 15 | 23 16 
; 4 174 x 
| 
Ig 20 i 13 
| , 
1] 1 24 6 13 
1} 13 26 74 12 
Open Type. 
Chain Square Section es Outside 
DV Aiotar, of Spring. Pearce of Spring. Winneter: Number of Coils. 
= Sen. 
Inches. Inches. Inches. Inches. 
$ 4 15 33 16 
3 | 3 3 
H 4 174 44 14 
| 1} 20 64 13 
1} BS 22 74 13 | 
| 
V4 1g 23 | 83 12 
| 


Taking these figures for the “open” type of spring, and using the ordinary deflection formula for 
. i=} . . Ld . o. 
square-sided springs, it would appear that the springs at present fitted would close at a smali pull on 
the chains. 


While this is perfectly suitable for all normal conditions of steering in the open sea, any blow which 
the rudder receives when the working load is being taken by the chains, is transmitted direct to the 
chains, and the springs due to being closed solid, do not absorb any of the shock. Nevertheless, it is 
unusual to find a spring broken in the coil, although these have been found, upon oc vasion, to be 
compressed solid, due to lack of attention. In the event of a buffer spring breaking in the coil, it does 
not mean a complete breakdown of the gear, as the spring is in compression and the strain is taken by 
the tie rods, although the chains would require to be adjusted for the alteration in length. 


Apparently, it is quite a common practice in shipyards to buy the coil of the spring and make up 
the remainder of the fitting and, apart from any test which is put on springs in the makers’ works, no 
further test is carried out, except in exceptional cases, 


6 


It has now been advocated by the Steering Gear Committee that the buffer springs should be of such 
a diameter and number of coils that they will close solid at about seven-eighths of the proof load, and 
the following table is a short extract from the table given in their second report. 


Open TYPE. 


Chain Square Section Mean Diameter | Minimum Number) Minimum Length 
Diameter. of Spring. of Coils. of Coils. Uncompressed. 
Inches. Inches. Inches. Inches. 
1 3 23 * 23 
5 mi 375 12 134 
3 1 95 
{ 1; 435 11 19 
I 1} 62 LOS 244 
1} 17 8 10 7h Sa 
14 24 913 10 347 | 


In the majority of vessels, the normal tension in the chains provided by the tightening of the Warwick 
screws is too small, a fact which has been proved by the chains, on occasion, slipping off the fairlead. Due 
to this small initial tension in the chains, the rudder is apt to swing and chatter in a seaway, and in order 
to combat this tendency it appears to be the custom of the ship’s officers to have the friction brake partly 
screwed down and to leave it in this position. It is a practice which cannot on any account be defended, 
as the steering gear is working continually against a load which it is not designed to overcome, leading to 
additional wear on the gear and also on the friction brake. 


It has been suggested that the springs should be compressed by the Warwick screws, with no load on 
the chains, to such a position that the tension in the chains will be equivalent to half the working load, 
and the table of proposed springs published in the second report gives this position for each size of spring 
and the Committee have advocated that each spring should bear marks corresponding to the working load 
and one half the working load, as a guide to the adjustment considered necessary. 

In this way, the tension in the chains will always be maintained under ordinary conditions of steering 
and the rudder will be reasonably controlled without the assistance of the brake. When the rudder is 
put hard-over when going at full speed, the working load will cause the spring on the working side to 
compress to the amount corresponding to this load, and the spring on slack side of the chain will elongate 
to its original ‘no-tension” position, without permitting any slack in the chain. 


In this position, any excess load due to a blow on the rudder will be absorbed by an additional 


compression of the spring but the rudder will only move when the blow produces a force in excess of the 
tension in the chain. 


In the usual arrangement, the buffer spring is placed at some distance from the quadrant, a position 
which, to some extent, can not be avoided, due to the length of chain which is required to allow the 
rudder to swing to the hard-over position, but, in some cases, an unnecessarily long length of chain is 
provided between the quadrant and the spring, in order to allow the chain to pass round a fairlead. Any 
shock on the rudder is first transmitted through that piece of chain between the quadrant and the 
spring, which has to take the full shock without any relief. The best position for the spring is as 
close to the quadrant as possible, and probably the most satisfactory results have been obtained by 
incorporating the springs in the quadrant as shown in Fig. 2. 

The Steering Gear Committee have now recommended that two buffer springs be provided on each 
side of the ship, one near the steering engine and one near the quadrant, or incorporated in a spring 
tiller. It has been suggested in some quarters that the maximum shock to which the steering chains 
and rods are subjected is that produced by the steering engine, instead of the more generally accepted 
opinion that it is produced by a heavy sea on the rudder. 


STEERING Rops, SPARE LINKS AND SHACKLES. 


The diameter of the stecring rods is required, by the Rules, to be from 4}; in. to 2 in. larger than 
the diameter of the chain, giving a stress of from 10 to 114 tons per sq. in. at the proof load of the 
chain, and the rod connections shown in Fig. 3, are of approximately equivalent strength to the rods 
required by the Rules. These diagrams have now been issued in the second report. 

If reference is made to the damages investigated by this Committee, it will be seen that the total 
damages to rods in the ten years was 13, an average of 1°3 per year, and these include breakages in the 
weld, in the jaws of the connection and also failure of the pin, and it is suggested that the majority of 
these are more likely to be due to wear than to any fault in the original material. 


It has now been recommended that the material of the rods be tested, that the finished rods, if 
welded, be tested to the proof load of the chain, and that, if the rods be made of steel, it is undesirable 
that the forked ends be attached by means of a blacksmith’s weld. 

The proposed sizes for shackles, also shown in Fig. 8, are generally in accordance with those 
considered by the Home Office and other regulations as equivalent to the strength of the chain. 

There are no standard sizes for shackies, and the shackle pin is anything from 1 to 12 times the 
diameter of the material of the shackle, but in majority of cases may be taken as } in. larger than the 
material of the shackle. 


It is the usual practice, at present, to use a shackle larger than the chain, but, due to the variation in 
width in the link of the chain, it is not always possible to get the pin of the larger shackle through the 
short link of the chain. For short link chains used for cranes, etc,, which comply with the standard laid 
down by the Home Office regulations mentioned previously, it is not possible for the pin of the “equivalent” 
shackle to go through the short link, and a long link is essential at the end of the chain. 


In the same way with steering chains which comply with this standard, it has been found impossible 
to use a 3 in. shackle with a 2 in. chain without the use of a long link. 


A long link at the end of the chain is essential to take the bow of the shackle, but it will be found 
that the usual dimensions of short link chain will take the proposed size of shackle pin. 


The proposed connecting links should be useful in the event of a chain breaking in order to effect a 
temporary repair with the least amount of trouble. 


The practice of fitting long links at the end of steering chains seems to vary considerably. In some 
gears a long link is provided at the connection of the chains to the rods, and in some, three long links 
are provided for use in the event of the chain requiring to be shortened due to stretching. It seems that, 
with the normal dimensions of chain, a long link is only necessary where the how of the shackle has to 
pass through the chain, such as the connection to the quadrant, and even in a case of this kind, a 
connecting link, such as those shown in Fig. 3, could be used in place of a shackle. 


The proof loads on sthe shackles used for lifting purposes depends on the size of shackle pin fitted, 
and the following table gives a comparison of the loads used in one of the private chain-testing 
establishments for shackles with pins of the same diameter as the chain, and also those for shackles with 
pins 1°2 times the diameter of the chain taken from Mackrow’s Pocket Book. 


| Diameter in inches... Bie 4 5 ; i 1 1} 1} 13 14 
I—— | A Mi = a 
| Chain proof load in tons anne | wes! 3 64 93 12 153 | 18% | 228] 27 
Shackle proof load in tons from 1 ; = 7 
; 4 ‘ Z v5 ( 8 0 4 
testing establishment a 2 ; : : 14 
Shackle proof load in tons from , a re : ; A 
~ 1 ol > 3 Ld 6 1 
Mackrow |i, eee 2 6% 9 11g | 14 17 201 


8 


Those given for the testing establishment appear small, but as the safe working load is taken as 
one half the proof load, it merely means the safe working load is reduced in proportion. 


The Steering Gear Committee have now recommended that the shackles and connecting links be 
tested to the proof load of the chain. 


WARWICK SCREWS. 


If reference is again made to the cases of damage examined by the Steering Gear Committee it will 
be seen that only 11 cases were due to failure of the Warwick screw, or just over one per year, Thus it 
can be assumed that the existing practice is perfectly satisfactory, both as regards dimensions and 
material, as the damages which have been found have mostly been due to the stripping of the thread 
through lack of attention and the fracture of the ends due to wear. 


However, the Steering Gear Committee have included a sketch of this fitting, together with detailed 
sizes, in their second report. This is shown in Fig. 4 in conjunction with the following table. 


Rod. Chain. A B Cc D £ F H | KandL t | T 
Inches. ine Inches. | Inches. Inches. Inches. | Inches. Inches. | Inches. AR Inches. Inches. 
s| 3 rer Nae Walle ern occ on (mle etl ag i ti = 
re Ge oa tee ee ema tae Ree mn et a ae ae aU | 
Rees) eis Serer ce eae an ee a Mae 

| 
hols ee We: Pe ois | 15 | 18h i 21 gh ae 
brig eevee Pret fear ele alee ome ee 
He dety, .)s RHi Aae 1 kb) Oe h2tba |) ob ope 8 gs | 3h 
2 12 24 24 1 i 43 24 294 | ] 33 16 3 i 
hs | j fl eal | 


These figures give a diameter at the bottom of the thread jj, in. greater than the rod appropriate 
to the gear and are based on the British Standards Institution Specification for rigging screws, with an 
increase of strength in the bottle and the addition of locking nuts. 


They also recommend that the travel of the screwed ends should allow a shortening equal to at least 
two links of the corresponding chain, and, if the screw is in the extended position when the new chain is 
originally installed the travel proposed may, to some extent, obviate the necessity of shortening the chain 
by removing links. The Committee have also recommended that the Warwick screws be tested to the 
proof load of the chain and stamped with this load, and the corresponding size of chain. 


An alternative type of screw which is occasionally fitted, has the centre portion forming the screw 
and the end portions as the outside casing, and while this does not appear to be quite as suitable as the 
type mentioned above, the total of damages is so infinitesimal that no differentiation can be made. 


A type of screw which is not satisfactory is that in which the outer casing is parallel and the screws 
are threaded through a thimble which is welded in position at the ends. These thimbles are a source of 
weakness in that they may be pulled away from the outer casing. 


FAIRLEADS AND THE CONNECTIONS TO THE Drck. 


The Rules state that the leads of the steering chains and rods should be as direct as possible, but in 
the vessels in which the chain drum is carried through the after end of the steering gear house, the right 
angle hend at the hatch side or ship's side can not be avoided, 

The Steering Gear Committee have advocated that, where the angle of the lead of the chains round 
the fairlead is less than 120° the diameter of the sheave, at present required to be 16 times the diameter 
of the chain, should be increased by 25 per cent. This increased diameter, if the recommendation is 
acceded to, will probably lead to a slight reduction in wear of the chain due to the less severe nip in the 
chain round the fairlead and would be of benefit in this respect. 

Fig. 10 shows two different types of fairlead block, both equally satisfactory. The right hand 
sketch in conjunction with the following table gives the practice of two firms, makers of patent fairleads. 
It sbould be noted that the centre bearing is of greatly increased diameter, incorporating an oil reservoir 
in the centre and the attachment to the deck is probably in accordance with the usual present day 
practice. 


] 
Diameter at | Diameter Overall Height from Diameter Number Diameter 
Size of Chain. | Centre of of Heicht Base to Centre of Bolt - of of 
Chain. Base. os“ | of Chain. Circle. Bolts. Bolts. 
Inches. Inches. | Inches. Inches. Inches. Inches. Inches. 
p12 | (18 17} 64% 38 4 6 ; 
q-18 15 19] 74 4 16 6 # 
1-15 17 224 8 44 1s} 6 a 
| 
1g-lys | 19 244 84 5 193 8 1 
1 5 g 2e1 7 m3 913 2 
l7-lye 21 265 95% De 214 8 1} 
13-14%, 2 28% 105 6 234 8 1} 
| | 
14-17%, 20 31 ih 6 254 8 1} 
| 


Neglecting the additional stress induced in the fastenings to the deck by a blow on the rudder and 
considering that occasioned by the working load on the gear, the maximum load on these fastenings is 1*4- 
times the working load, when the angle of the chain round the sheave is 90. Taking the figures in the 
table given above, the resulting shear stress is approximately 2 to 2% tons per sq. in., varying slightly over 
the complete range of blocks. 

Assuming a resultant pull on the fairlead equal to the proof load of the chain the figures vary from 
24 to 4 tons per sq. in. 

When the sheave is an appreciable distance above the deck, an additional stress is introduced in that: 
part of the connection of the fairlead to the deck outside the angle formed by the chains, but in the usual 
arrangement this may be neglected. : 

The Steering Gear Committee have recommended that this stress, due to a pull on the fairlead equal 
to the proof load of the chain, should not exceed 5 tons per sq. in. Thus the fitting shown above is 
stronger than that suggested. 

Although this type of fitting varies considerably, ip is thought that in the majority of classed vessels 
the fairlead connections to the deck are in excess of this standard and they have given practically no 
trouble. 

The shear stress in the pins of the sheaves, if of Rule size, is 2°7 tons per sq. in., taking the 
maximum force as 14 times the working load. 


10 


The same load is taken by the blocks which carry the chains from the upper deck to the poop deck, 
but here the centre pin is in double sheer. It has been suggested that the horizontal sheave on the deck 
should be made in a similar manner, with a bearing for the top of the pin. A sheave of this type is 
shown in the left hand sketch of Fig. 4, and, while it would be of increased strength, the figure of 2°7 tons 
per sq. in. given above for shear stress is.so small that the introduction of this top bearing does not seem 
essential. 


The report also recommends that the deck below the fairlead should be of ample thickness and a 
doubler fitted if necessary. It also recommends that the pins, frames and baseplates of the fairleads 
should not be made of cast iron. 


If brass bushes are not provided, the fairlead pin is a part of the gear which is very liable to wear if 
not properly lubricated. The pins should be kept well greased to ensure that the sheave revolves freely, 
as in some cases, they have been found to be jammed with the chains sliding round them, instead of the 
sheave revolving. 


QUADRANTS. 

The different types of quadrants are many and a sketch of one design is shown in Fig. 1. If 
quadrants of Rule size are fitted and the number of rivets attaching the arms to the plate is sufficient 
to withstand the shear, no trouble should be experienced in this portion of the gear. A source of 
danger is the inadequate attachment of the chain to the quadrant. 


It will be seen that the shackle at the end of the chain, in the quadrant shown, is not up to the 
standard set forth in the new proposed table. If this standard is accepted, this shackle would require to 
be 12 ins. instead of 14 ins. as fitted. Examination should also be made of the fitting on the quadrant, 
in order that the strength of the attachment may be made equivalent to the strength of the chain. 


Care should also be taken to see that the quadrant is properly fitted and shrunk on to the rudder 
stock. When this is not an effective fit initially, it is liable to become loose, chewing up the keyway, 
putting the quadrant out of dead centre and often, eventually, twisting the rudder stock. Special 
attention should be paid at all surveys to this key. 


A case, which shows the necessity for examination of the original design, was brought forward 
some time ago. Due to the sheer of the deck and the position of the aft guide sheaves being too close 
to the quadrant, the pull of the chains when approaching the hard-over position was in a downward 
direction. No guide runners were fitted under the quadrant and, during the course of heavy weather, 
the quadrant bent considerably and the rudder stock was twisted. While this may be possibly an 
isolated case, it shows the necessity of efficient guide runners being fitted under the quadrant and also 
attention being paid to the direction of pull of the chains. 


In an alternative design of quadrant, the chains are carried as far as the centre line, where they are 
attached to an eyeplate. The quadrant requires to be approximately three quarters of a circle to give 
sufficient bearing surface for the chain when the rudder is hard over. Again the connection of the eye 
plate to the quadrant should be specially examined. 


A good type of quadrant is the “‘spring-harnessed” quadrant and tiller shown in Fig. 2. _ In this fitting 
a loose quadrant is connected by means of strong springs to the tiller which is shrunk on, and keyed to, the 
rudder stock. The quadrant and tiller are made of cast steel or a forged steel tiller may be fitted, if so 
desired. 


An excessive blow on the rudder is taken up by the springs, before being transmitted to the chains. 
This appears to be a much more logical way of dealing with the shock. The Rules allow the depth of the 
boss and the size of the arms of this loose quadrant to be reduced from the dimensions required for a 
keyed quadrant. It is sometimes the practice to cut a keyway in this loose quadrant for use in the event 
of any damage to the springs or tiller and, by doing this, an efficient secondary method of steering is 
provided if the main tiller is put out of use. 


Quadrants, fabricated and welded, have been designed and approved and although the majority are 
for use with gears at the rudder head, some are for rod and chain gears. The arms are built up of a 
vertical and two horizontal plates in the form of an H bar, the section modulus of which is the same as 
that of the arm of the Rule quadrant. Tripping plates are inserted to take any twisting stress. 


11 


Rupprer Brakes. 


In one of the enquiries mentioned previously, some doubts were cast on the efficiency of the friction 
brake, which failed to hold the rudder in an emergency. The brake in the vessel in question was of the 
screw down friction type and it is possible that the brake had been kept partly screwed down and the 
friction segments had worn away. The rudder brake should only be used when it is desired to change 
over to the auxiliary gear, or when the state of the weather is such that it is considered absolutely 
necessary to check the action of the quadrant. 1s is possible that this practice may be responsible for a 
number of the broken chains which are reported. The brakes fitted can be divided into two principal 
types, friction brakes and oil-cushioning brakes, and Figs. 5 and 6 show a selection of the two types. 
Probably the most popular brake and one which has given every satisfaction, when well looked after, is 
that shown in Sketch 1 of Fig. 5. 


This brake is securely bolted to the quadrant and a double grooved sheave is fitted, free to revolve 
on the axis of the base plate. At the top and bottom of the sheave are wood rings in segments, the 
bottom ring being inset into the base plate and the top ring into a loose plate, which is prevented from 
turning by means of four pins. 


A strong wire is connected to a substantial bracket on one side of the ship and, after passing round 
the pulley in the grooves, is connected to a bracket on the other side of the ship, and is set up taut by a 
screw, As these brackets have to take the full shock when the brake is hard down they should be very 
strongly constructed, 


In order to apply the brake, the hand wheel is turned, forcing down the top loose plate and the 
grooved pulley is pressed against the wood and retarded. Any degree of braking can be obtained. 


In the event of a breakdown in the steering arrangement the brake can be screwed hard down until 
either the auxiliary gear has heen coupled up, or the affected part repaired. 


It can be seen that if this brake is kept partly screwed down the wood rings will gradually wear away 
necessitating harder screwing down, until such time as the brake will be useless when actually required. 
The upkeep of these brakes is important. They should be examined for wear periodically and should, at 
all times, be well greased. 

Sketch 2 of Fig. 5 shows another type of friction brake. In this case, the brake acts automatically, 
once the necessary initial adjustment has been made. Due to the travel of the ends of the rope in a fore 
and aft direction, the rudder is allowed to turn slowly when driven by the chains. It is claimed that 
when the sea strikes the rudder, the wires tighten round the brake band, causing this band to come in 
contact with the wood blocks, owing to the increased speed of the rudder. When the force of the blow 
passes the ropes slacken and the friction is released. In the event of a breakdown, the stretching screw 
is tightened up until the rudder comes to rest. Sketches 3, 4 and 5 show other types of friction brakes 
and the drawings are self explanatory. 


With regard to Sketch 5, this depicts a very efficient type of brake provided the quadrant is of such 
construction that it is suitable, 

Sketch 6 shows the “slot and pin” method, which is sometimes fitted in small ships. This is not a 
brake, and it is too sudden in its action and does not allow any give in the quadrant. 


Fig. 6 shows three types of hydraulic rudder brakes. 


Sketch 1 illustrates a patent brake fitted to the rudder stock. It consists of a rotary piston, keyed 
to the rudder stock and moving in an outside casing which is divided into two compartments, connected 
hy ports which can be closed by means of hand-operated valves. The casing is filled with oil and is 
maintained full by oil reservoirs fitted to the top of the casing and provided with non-return valves, 


When the rudder is turned the rotary piston sweeps the oil from one compartment to the other 
through the valve port. 


The braking action is produced by regulating the flow of liquid by opening or closing the valves, 
and by closing the yalves completely the rudder can be brought to rest. The sketch also shows the 
fitting used as an emergency means of steering. The compartments are connected to an oil pump by 
pipes which are normally out of the cirenit but, in the event of a breakdown in the main steering gear, 


12 


the valve ports connecting the compartments are closed and, by means of a change cock on the pump 


the oil is driven into either port or starboard compartments as required. In this way the rotary piston 
is moved by the oil pressure. 


It is claimed that, up to 6 ins. diameter of stock a hand pump only is required, and above that 
diameter a power pump, in order to steer the ship at half speed. 


Sketch 2 shows a very effective type of hydraulic brake fitted to the quadrant. It consists of a single 
cylinder, swivelled and free to move in a fore and aft direction, the ends of the pistons being attached 
to brackets at the ship’s side. 


"A circular seat, attached to the quadrant, receives a circular block with a slot across it, and in this 
slot, a parallel slide which is part of the cylinder, rests, so that the fore and aft movement due to the 
quadrant swinging is taken up on the cross slide and the swivelling movement is taken up by the block 
revolving in its seat. 


The extreme ends of the cylinder are connected by a bye-pass pipe with a regulating valve. When 
the quadrant moves, the cylinder travels along one of the pistons, driving the oil along the pipe to the 
other end of the cylinder, the amount of liquid flowing depending on the regulating valve. Special 
notice should be taken that the makers of this hydraulic brake always recommend that the shut-off 
‘alve should be left fully open in normal circumstances, and thus the cushioning effect of the oil is the 
only rudder restraint. It is a very simple matter to clos? the regulating valye and bring the quadrant 
to rest. 


Several brakes of a similar type to this have also been fitted. Two cylinders may be used, one on 
each side of the quadrant connected by a pipe with a regulating valve. The fitting on the quadrant is 
held between swivel blocks on the ends of the pistons, in a somewhat similar arrangement to that 
employed in an electro-hydraulic gear. A sketch of this type of brake is also shown in Fig. 5. 


Alternatively a tiller, fitted athwartship:, may be keyed to the rudder stock and the hydraulic 
cylinders placed in a fore and aft direction, the pistons being connected to the ends of the tiller and the 
cylinders joined by a pipe as described above. 


All these brakes are of the same type, depending for their efficiency on the movement of oil past a 
regulating valve. 


These hydraulic brakes have also been fitted as auxiliary means of steering by connecting the 


cylinders to an oil pump in the same way as described previously in the case of the brake shown in 
Sketch 1, Fig. 5. 


While on the subject of rudder brakes, it might be well to mention those usually fitted with the 
type of gear at the rudder head. This consists of a brake similar to that shown in Sketch 5 of Fig. 4. 
The brake quadrant is fitted underneath the main quadrant, and 1s sometimes incorporated in the same 
casting. The brake is adjusted by means of the hand screw gear, which is fitted in such a position as to 
be accessible at any angle of the quadrant. 


An alternative type is an hydraulic gear which combines a brake and auxiliary means of steering, 
and consists of two cylinders abreast with hydraulic rams as shown in Fig. 6, This auxiliary means of 
steering is provided in lieu of, or in conjunction with, the more usual fitting of a hand gear working 
through a shaft and worm wheel direct on to the toothed quadrant. 


While it is not claimed that particulars of all types of rudder brakes have been given, the majority 
of them have been mentioned, and any other types fitted are merely modifications of these. 


Too much stress can not be laid on the fact that this portion of the steering gear becomes of para- 
mount importance in the event of a breakdown, and the primary need is for quickness of action in 
controlling the movement of the rudder. For this reason, the maintenance of the brake is of vital 
importance and periodic examination is a necessity. The Steering Gear Committee have made no recom- 
mendation regarding this important item of the gear, although they state in their report that “to be 
effective the brake should be gradual in application but finally positive in its action.” 


2 
» 


_ 


While the patent brakes shown would probably be efficient for any diameter of rudder stock, some of 
the designs of friction brakes, while perfectly suitable for small vessels, would not hold a large rudder 
stationary. The area of the friction surface should bear some relationship to the diameter of the rudder 
stock but the general opinion is that the present practice is quite satisfactory provided the brake is 
lubricated and not allowed to be become useless through neglect. 


It is still the practice on some ships to rig a relieving tackle consisting of rope and blocks, forming 
two separate tackles connected together as shown in Fig. 7. This is a relic of earlier days of hand steering 
and was provided to prevent the shock caused by a blow on the rudder being transmitted to the hand 
steering wheel. 


Its use under present conditions of chain steering, with buffer springs incorporated, appears rather 
unnecessary, provided the tension in the chains is satisfactory but it is much preferable to the practice of 
screwing down the brake. Although it relieves the buffer springs of part of their work during heavy weather 
and has the effect of damping the movement of the rudder in the event of the chain breaking, it is 
insufficient, alone, to hold the quadrant fast. 


On the other hand if this relieving tackle is kept in position at all times, the steering engine requires 
to overcome an additional resistance which is bound to affect its efficiency. In some small coasting vessels 
at present in service this relieving tackle or aiter natively, the secondary means of steering, consisting of 
blocks and wire ropes, is used in lieu of a brake. This may be suitable for this type of ship but would 
not be suitable for a vessel of any size as, unless this tac kle is actually fitted to the quadr ant when a 
breakdown takes place, it is practically impossible to connect up when the quadrant is swinging. 


AUXILIARY MEANS OF STEERING. 


The Rules require that a secondary means of steering be prov — for use in case of failure of the 
main gear, This, in general, consists of either a block and tackle a rangement with the motive power 
prov ided by the after winch or, alternatively, a hand gear of the left eal right handed screw type. 


The main drawback to the block and tackle arrangement is the difficulty of connecting the gear to 
the quadrant in heavy weather and also, after the gear has been rigged, the after winch has to be 
operated under wee ther conditions which are not conducive to work, on an open poop or shelter deck. 
There appears to be no generally practicable method of providing protection for the men operating the 
power winch. 


The strength of the main gear is based on the designed speed of the vessel with a suitable factor of 
safety. The working conditions of the auxiliary gear are entirely different as it is not expected that any 
vessel will be driven at the maximum dig when the auxiliary gear is in use, and it is probable that the 
auxiliary gear will be used merely to keep the vessel head on to the seas. The weather conditions, 
however, will probably be severe and the force of a heavy sea on the rudder bears very little relation to 
the speed of the vessel. 


The strength of this type of gear is dependent on the number of pulleys in the sheave and, due to 
the fact that the pull of the winch is limited, it may only be possible to increase this strength by 
increasing the number of pulleys, and thus decreasing the speed of turning of the rudder, 


The Steering Gear Committee have recommended that the auxiliary gear should be equal in strength 
but notenecessarily in power to the main gear, and Fig, 8 shows an auxiliary gear of the block and tackle 
type, complying with this requirement. 


It should be noted that one set of pulleys of the tackle is connected direct to the quadrant. In some 
cases this cannot be arranged, and the length of wire between the ee and the pulleys would require 
to be suitable for the full load, in this case 4} ins. G.S.F.S. wire, with a breaking load of 64°6 tons. 


The hand gear of the left and right handed screw type is not a usual feature of the later vessels fitted 
with rod and chain gear, the majority of these being provided with an auxiliary gear of the block and 
tackle type, but it is quite common in older vessels. 


14 


The following table in conjunction with Fig. 9 is taken from the British Standards Specifications for 
hand gear dated 1923. This specification was never published but the figures show the sizes considered 
suitable at that time. ‘The dimensions for the gear are given up toa 12 inch diameter stock, so that there 
was no question of confining the use of the gear to small and medium sized vessels. 


Diameter of Number and Diameter of Steering Diameter of 
Rudder Stock. Wheels (over handgrips). Serew Spindle B. C. 
; re ‘Inches. ma 7 Feet Inches. Pat Inches. Inches. 

34 One 4 0 24 8} 
I * 4~ 0 23 8} 

D F 4 6 34 10 
6 e Hf) 6 4 134 
7 ? 5 «6 | 43 | 143 

8 ¥ 6 i) | 5} | 17 

i) Two 6 6 6} 19 

10 | 3 6 6 7 20 
11 a 7 0 73 214 

12 H yi 6 8} 23 

| 


As far as can be found out, this is the existing practice for hand gears. 


The gear consists of a screw, one half of which is cut with a left hand thread and the other half with 
a right hand thread, and sleeves which move up and down the screw, are attached to a tiller on the rudder 
head by tie rods. When the wheel is turned the sleeves move in opposite directions, and the tie rods 
pull the rudder round. When not in use, the pins connecting the tie rods to the sleeves are withdrawn. 


As this type of hand gear does not incorporate any shock absorbing arrangements, the force of a 
blow on the rudder is transmitted direct to the tie rods, and in order to dampen the movement of the 
rudder, when steering was carried out by hand, it was the practice to rig a relieving tackle as described 
previously. 

With a spring harnessed tiller, this type of hand gear has been fitted in such a way that the springs 
of the quadrant provide the shock absorbing qualities for the hand gear as well as the main gear. 


Instead of being connected direct to the rudder head, the auxiliary tiller, to which the tie rods are 
fitted, is bolted to the boss of the loose quadrant, thus transmitting the turning motion through the 
loose quadrant and the springs, to the tiller, which is keyed to the stock, In this way the springs take 
up the shock of a heavy sea on the rudder for the hand gear and the main gear. 

It can be seen that this method is much preferable to the commoner type, but is only suitable for 
use with the spring harnessed quadrant and tiller usually found in the Wilson-Pirrie type of gear. 

Another type of hand gear is that operating through a worm gear and friction clutch to a toothed 
quadrant, keyed to the rudder stock, but as this type is more commonly incorporated in a steering gear 
at the rudder head, it will be mentioned again tater. 

The Steering Gear Committee have now intimated that, in their opinion, the hand gear of the left 
and right handed screw type is not suitable for large vessels and have suggested a limit of size for 
installing it, above which limit they advocate an auxiliary gear of the block and tackle type. 


15 


TESTING AND UPKEEP. 


There is no doubt that if the rod and chain gear is not maintained in an efficient condition, it is 
more liable to damage than any other type of steering gear and, from this it follows that periodic 
examination and overhaul is a necessity. . 


With new ships, when the steering chains are originally installed, they are required to have passed 
the tensile tests laid down in the Rules at a recognised Proving House or, at the makers’ works in the 
presence of a surveyor. 


When chains require to be renewed or repaired due to wear or flues, either a complete new length 
of tested chain is fitted or the affected links are replaced by new links cut from a tested chain. In cases 
where the completed chain is not tested, the joining links and any occasional links which are inserted, 
are not subjected to any test. Mr. Shaw, in his paper last year, advocated that, in cases of part renewals 
of chain, where new links are fitted, the length should be tested on completion, and he stated, in the 
discussion, that the retesting of chains after part renewal is now common in districts where testing 
machines are available for the purpose but that his experience in latter years did not include districts 
where such facilities did not exist. 


Even in some ports where a testing machine is not available it has been the practice to suspend 
the chain with the required load on the end. Although this is quite a suitable method, it seems to be 
rather a difficult proposition to carry out for the larger diameters of chain, say 14 in. diameter, where the 
proof load is 27 tons. 


While the practice of testing repaired chains is common in this country, steering chains are also 
repaired in a great number of ports in the world where the appliances are not available for testing. 


It is the general opinion that annealing, if properly carried out, is beneficial in relieving the chain 
of stress, and to bring it back to more or less its original state after hardening by straining. 


The only point over which there appears to be a divergence of opinion is the advisability of annealing 
chains without subsequent retesting, due to the effects of the annealing on the welds of the links. 


In a number of papers read before the Staff Association reference has been made to the undesirability 
of the present method of so-called annealing by passing the chain through an open fire. 


To correctly anneal a chain, the length of chain should be raised to a temperature of about 1400° F. 
and allowed to cool slowly. The number of thermostatically controlled oil-fired or gas-fired chain 
furnaces is limited. although on the increase, and the chain is usually heated in an open fire of 
temperature unknown and allowed to cool in the open. The probable result is that each portion of the 
chain is heated to a different temperature. 


Sometimes the chain is merely dragged through an open fire and thrown on the floor to cool. — It is 
quite possible that this does more ‘harm to the chain than good, the only point which may be mentioned 
in its favour being that it burns the grease off the chain, thereby allowing a closer inspection and the 
easier detection of flaws. 


In those ports, where there are no chain furnaces, in which the temperature can be regulated, a 
wood or charcoal fire should be built comple tely enclosing the length of chain, and after heating to a dull 
red heat, the chain should be allowed to cool in the fire. 


At present, the practice regarding the period of time between successive annealing varies considerably. 
In general it is carried out at most heavy weather damage surveys when the gear is completely dismantled 
and examined. Apart from this, some owners require ‘it to be done at the annual dry docking, but the 
time for this is generally so limited that it is left to longer periods and, in some rare cases, is only done at 
Special Surveys. 


The practice regarding the pericdic examination of rod and chain gears is practically uniform. 
Owners usually have the whole gear, including the engine, opened up and examined at ail heavy weather 
damage surveys, at some grounding and collision damages where the rudder has been affected and at 
Special Surveys. 


16 


At other surveys, in dry dock or afloat, the gear is examined superficially, as far as is possible, and 
these examinations occur, on the average, at intervals of less than one year. 

The amendments to the Board of Trade Rules for the Survey of Passenger Vessels, published in 
1932, require that all steering gears be opened up and examined at least once per year, 

The Steering Gear Committee haye now recommended that all rod and chain gears be opened up and 
examined every three months, and surveyed by a competant authority at periods not exceeding one year. 


SPARE GEAR. 

The question of repairs, and more particularly the testing of repaired components, does not_ become 
of such paramount importance if a satisfactory number of spare parts is carried, The spares advocated 
by the Steering Gear Committee are as follows:—One complete spring, one extra spring, two tested 
chains equal to the longest length in the gear, two Warwick screws, four shackles, four connecting links, 
and four rod pins. 


Weak OF CHAINS. 

It is agreed that the chains are the part of the gear most subject to wear, due to chafing on the 
guide channels and rollers, and wearing at the bight of the links. In order to ensure that a definite 
standard is maintained, below which the strength of the chain should not be allowed to fall, the Steering 
Gear Committee have recommended that a maximum amount of wear for each size of chain should be laid 
down, and these figures have been published in their second report. The percentage wear allowed is ¢ 
reduction in area of approximately 15 per cent in the larger diameter of chains to 80 per cent in the 
smaller diameter. 

On comparing the figures now published with those already in use for chain cables, it is found that 
they are practically the same except that between 1{ ins. and 1°, ins. original diameter, the amount of 
wear allowed is .)5 in. less than that allowed for chain cables. 

As the wear of the chains takes place on one side, the reduction is specified as a mean diameter of 
chain. 

As the principal advantage claimed for the rod and chain type of steering gear is its lower initial 
cost, aluhough the upkeep costs are probably higher than other types of gear, any alterations to the 
existing practice will tend to counteract this initia! advantage and will also raise the subsequent costs. 

In all probability this would give a further fillip to the general tendency in modern practice to fit 
the steering gear at the rudder head, a position which, from the point of view of efficiency, is much 
superior to the older type of gear, transmitting the power from the engine room to the rudder by means 
of chains. 


A Parent ARRANGEMENT ‘TO TRANSMIT THE MOVEMENT OF THE STEERING ENGINE 
TO THE RUDDER. 

A type of steering gear which, it is claimed, has all the advantages of the rod and chain gear, 
without its accompanying disadvantages has just been approved and is at present being fitted in a vessel, 
to replace the existing rod and chain gear. 

It consists of a twin-cylinder vertical engine, installed in the thrust recess and controlled from the 
bridge by the usual combination of rods and bevel wheels. The movement of the engine is transmitted 
to the quadrant in four stages. 

A horizontal line of mild steel shafting, supported in a suitable number of bearings, is carried along 
the tunnel to a gear case in the tunnel recess. A stuffing box is provided where the shaft passes through 
the thrust recess bulkhead and the aftermost shaft is connected to the gear shaft by a claw coupling. 
The gear is of the worm and wheel type, with a suitable velocity ratio. 

From the lower gear box, a vertical shaft, also supported in hearings, is led up the tunnel escape 
to another gear of the worm and wheel type, on a level with the position of the quadrant. The lower 
coupling of this shaft is of the claw type and the upper coupling keyed to the shaft, so that the weight 
of the shaft is supported at its upper end. 


17 


From this upper gear box, a horizontal shaft is led to a cast steel drum, keyed to the shaft, and 
supported in bearings. The drum is grooved for the reception of wires which connect the drum to 
the quadrant. ‘Two separate wires of tested quality are provided on each side, led through guide sheaves 
in order to obtain the pull in the required direction, and attached to the quadrant so that equality of 
tension is assured in the two wires at each side. 


The quadrant is of the spring harnessed type, working through a tiller, keyed to the rudder stock 
and somewhat similar in design to that shown in Fig. 2 and titted to the fore side of the rudder stock. 


The detail sizes of the gear depend on the diameter of the rudder stock but, for a 10 in. diameter of 
stock, the designer proposes a tunnel shaft of 2} ins. diameter and a velocity ratio, incorporated in the 
two gear boxes and the drum and quadrant of 800/1. 


The adyantages claimed by the designer are that the steering engine is always under the supervision 
of the engineer on watch, that the remainder of the mechanism is easily accessible for detection of defects 
and for any necessary adjustment and repairs. He also states that, due to the protection afforded, the 
gear will be free from damage by cargo, or heavy weather, and also that the transmission mechanism will 
work much more efficiently than the rod and chain gear. 


The advantages claimed as regards the shorter length of steam pipes and eontrol rods apply equally 
to this gear and that of the rod and chain type. As this is the first gear of its type to be fitted, the 
results of its working under sea conditions will be awaited with interest. 


STKERING GEARS AT THE RuppER Heap, 

In an attempt to improve the efficiency of the steering gear, the engine was placed nearer to the 
rudder head, generally in a house on the poop and the motion of the gear was still transmitted to the 
quadrant by means of chains, the only difference being that the lead of control rods and steam pipes was 
ionger, and that of the chains shorter. A number of these gears are still in existance on older vessels, but 
they have been completely ousted in new vessels by the Wilson-Pirrie gear transmitting motion direct 
to the quadrant. 


This gear consists of a two-cylinder vertical steam engine, on the crank shaft of which is a worm, 
gearing with a worm wheel, the movement being transmitted through this worm wheel shaft to a spur 
pinion gearing with the quadrant. 


The quadrant is free to move on the rudder stock and is connected by buffer springs to a tiller keyed 
to the stock. The engine control yalye may be operated from the bridge by means of control rods and 
bevel wheels, or by a steering telemotor, ‘There is also an alternative steering position on the after deck 
connecting with the control valve spindle by rods and bevel wheels and a control wheel is also fitted on 
the engine itself, so that three different positions of steering are provided, 


Generaily an economic valve is provided to ensure that the steam is automatically shut off from the 
engine as soon as the steering gear comes to rest. The control valve is moved back to its mid-position 
when the rudder angle corresponds to the amount of helm on the bridge wheel, by means of the hunting 
gear, in this case consisting of spur wheels and a floating lever, working from the main pinion, geared to 
the quadrant. 


The engine is either of the fixed-bed or sliding-bed type and they are in all esentials the same, the 

only difference being in the method employed in disconnecting the power gear when changing over from 
A ene ’ 5 D pits 
power gear to auxiliary gear. 

With the sliding-hed engine, the main holding down bolts are slacked off and the engine is moyed 
forward bodily clear of the toothed quadrant. With the fixed-bed engine, the same result is obtained by 
disengaging the worm wheel, driven by the engine, from the pinion which drives the quadrant. 

The rudder brake is similar to that shown in Sketch 5 of Fig. 4. The brake is operated hy a hand 
wheel and presses the brake against the quadrant. 

The auxiliary means of steering may consist of either a hand gear or a block and tackle arrangement. 
In most cases, eyes are fitted on the quadrant for block and tackle, even if a hand gear is also provided, 


18 


The hand gear consists of a pedestal on the top deck, driving a shaft by means of a worm and worm 
wheel, and on this shaft is mounted a pinion, gearing with an auxiliary toothed quadrant, keyed to the 
rudder below the main quadrant and extending aft. 


If a friction clutch is incorporated in the hand gear, the pinion is always in gear with the auxiliary 
quadrant and the friction clutch is tightened up when a change over is necessary. 


With the hand gear, without the friction clutch, when the hand gear is disengaged, the pinion is 
lifted up clear of the auxiliary quadrant and requires to be lowered when the hand gear is put into 
operation. 

When changing over from steam gear to auxiliary gear, the hand gear is engaged before the steam 
gear is disengaged and the rudder is always under control. Ifa friction clutch 1s provided, the operation 
is carried out by simply tightening up the clutch and no rudder brake is necessary, although generally 
included, but without this clutch a rudder brake is essential. 

Also, without the friction clutch, no arrangements are incorporated to take up the movements of the 
rudder due to shock, so that the gear is liable to be smashed by seas during heavy weather. With the 
clutch fitted the gear is not so liable to damage by shock. 


As has been stated previously, the Steering Gear Committee in their enquiry into the efficiency of 
hand gear on rod and chain gears, have stated that, even with a double hand wheel, operated by four men, 
it is doubtful if there is sufficient power to control a ship of more than 3,500 tons gross in heavy weather 
and they have recommended that, in a vessel over this size, an auxiliary gear of block and tackle should 
be employed, although this recommendation apparently does not apply if a friction clutch is incorporated , 


This block and tackle gear is the same as that described previously, with the exception that the wire 
has to be carried through the poop or shelter deck, round a guide pulley, to the after winch. 


The question again arises as to whether the auxiliary gear should be of equivalent power to the main 
gear. : 
While the description given is that of the most usual type of engine, each firm of steering gear 
makers have their own standard types. They may be horizontal engines driving direct to a quadrant or, 
in smaller vessels, a horizontal engine in conjunction with a left and right handed screw gear attached to 
the rudder head. 


SrTeamM TILLER. 


Another arrangement of engine fitted at the rudder head is the steam tiller. In this gear the tiller 
carries a two cylinder horizontal steam engine, which drives a worm, engaging with a worm wheel. This 
worm wheel is connected by a friction clutch to a shaft carrying a pinion, which engages with a rack, 
securely fastened to the deck. The steam is admitted to the cylinders through a trunion in a direct line 
above the centre of the stock. 

The control valve is operated by means of a telemotor or a standard fitted directly above the gear, 
and the control lever is pivoted at the centre of the rudder stock. 

As the movement of the telemotor opens the control yalye, the tiller moves round the rack, and 
the control lever automatically cuts off the steam when the required angle of helm has been obtained. 

The friction clutch operating the main pinion is capable of holding the rudder in any position, but 
if the rudder is hit by a heavy sea, the clutch allows the tiller to swing which moves the control gear, 
starts the engine and drives the tiller back to the required position. A hand gear, of the same type as 
that already described, and incorporating a friction clutch, is provided, working through an auxiliary 
quadrant bolted to the extension of the tiller forward of the rudder stock. 

Arrangements are also made for an auxiliary gear of the block and tackle type. 

When it is required to change over from the steam gear to the hand gear, the friction clutch of 
the hand gear is tightened up and that of the main gear slacked off. 

With a steam gear aff and an auxiliary gear of the block and tackle type, it is usual, on cargo 
vessels, for the same steam pipe to provide for both the steering gear and the after winch, so that, if 
the pipes on the deck are damaged, both main and auxiliary gear are put out of action at the same time. 


19 


The protection which is given to these pipes probably excludes any chance of this happening except 
in very exceptional conditions, but, in this respec t, an extract fram the Board of Trade Amendments to 
the Rules for Passe nger Ships, published in 1932, is interesting :—* the pipes should be used exclusively 
for the steering engine.’ 

The ideal arrangement is that in which the steam pipes for the steering gear are led along the 
tunnel and up the tunnel escape, thereby ensuring complete protection from, damage, and the ‘after 
winch is supplied from the deck line i in the usual way. 

While the lubrication of the steering engine is such that it does not require continual attention, the 
principal drawback to an engine of the type described is that it does not rec ‘eive the same care and 
attention during a voyage that is given to the inidship gear, unless the steering gear is capable of being 
reached from the tunnel by means of a tunnel escape. 


TELEMOTOR CONTROL. 


Moving the steering engine from midships to the rudder head entailed the lengthening of the lead 
of the control rods. Due to the awkward lead from the bridge to the extreme aft end of the vessel, 
an alternative method of control had to be found, and the telemotor control was introduced in 1888. 

The product of each of the telemotor makers varies slightly in design, although the main 
principles are the same in each case, the system consisting of a transmitter or steering telemotor on the 
bridge, two lines of copper piping and the receiver or motor telemotor in the steering gear compartment, 
operating tho control valve of the steering engine. 

The whole system is charged with non-freezing oil or a mixture of water and glycerine. 

This provides an hydraulic connection between the steering handwheel and the steering engine so 
that all movements of the handwheel are immediately transmitted to the engine. 

A sketch of one system is shown in Fig 11. 

The turning motion of the handwheel is transmitted through a pinion and spur wheel to a rack which 
operates the piston in the cylinder. The moyement of the piston, upward or downward, forces the fluid 
along one of the copper pipes to the receiver rams at the steering gear, returning the fluid along the other 
pipe. 

Special automatic and hand bye-pass valves, which open only when the rudder is amidships, are 
incorporated in the steering telemotor in order to relieve any excess pressure on the system and also to 
replenish the system if any leakage has taken place. 

In one type of telemotor, two cylinders are provided in the bridge transmitter, each with plungers, 
and the moyement of the wheel raises one plunger and lowers the other, producing the same result as the 
single plunger. 

The receiver in the engine room consists of one cylinder, with a division in the centre, free to move 
on fixed rams, bolted to a common bedplate. Fluid is forced into one compartment of the cylinder, thus 
moving the cylinder along the rams. The control mechanism of the steering engine is connected to the 
cylinder body, and thus any movement of the bridge handwheel is accurately transmitted to the valve of 
the engine, 

When the cylinder moves, the spring which is wound around the body is compressed, tending to bring 
the receiver back to the midship position when the handwheel on the bridge is released, An alternative 
type of receiver has the cylinder fixed and the plungers frée to move and each carries a crosshead, con- 
nected to each other by tie rods on which the springs are mounted. Any movement of the tie rods is 
made against the compression of the springs and these bring the gear back to the midship position when 
the pressure is removed. One crosshead is connected to the operating mechanism of steering engine 
control valve, so that the movement of the plungers is transmitted to the control valve. 

A charging tank and hand punip are provided with all designs to pump out and clean the system. 

The advantages of the telemotor control over the old method of shafting are manifest. The pipes 
can be carried round awkward bends where it would be impossible to take shafting, there is a lack of noise 
and the ease of manipulation is evident. 

The lubrication of the gear and examination for leakages should be carried out periodically to ensure 
efficient working of the telemotor control. 


20 


Enecrro HypRrAvuLic GHar. 

The two alternative types of gear. are a two ram gear or a four ram gear. With the four ram gear, 
two pumping sets with electric motors are generally provided, each set capable of working the rudder with 
two or four hydraulic cylinders in action, One pumping set therefore acts as a stand by. It is also 
possible. when necessary, for steering in narrow waters, for the two pumping sets to be used together, 
thereby increasing the speed of turning. A plan view showing an arrangement of a four ram gear is 
shown in Fig. 12. 

Two pairs of hydraulic cylinders are opposed to each other, the rams being coupled together and 
operating the tiller by means of swivel blocks. The tiller is shrunk and keyed on to the rudder post. 

The motive power is provided by rotary oil pumps, driven by constant speed non-reversible electric 
motors. These pumps are of two main types which fulfil the same function in slightly different ways and 
will be described later. 

The electric motors and pumps are continually running and the pumps are so designed that when 
the rudder corresponds to the position of the steering wheel on the bridge, no oil is discharged and the 
motors are running light. The operation of the pumps is controlled by the movement of the telemotor 
or by a handwheel and spindle from a position adjacent to the steering gear. 

Four valve blocks, one for each cylinder, are provided, and oil pipes are led from the pumps to each 
of these valye blocks and from each valve block to the corresponding cylinder. Cross over pipes are also 
fitted connecting up the valve blocks of the cylinders which work together, i.e., the valve block of the port 
forward cylinder to that of the starboard after cylinder, and that of the starboard forward cylinder to that 
of the port after cylinder. This ensures that, when the four rams are in action with one pumping set, 
the corresponding rams are working in unison. 

A floating lever is connected to the link joining the operating spindles of the two rotary pumps. One 
end of this floating lever is attached to the telemotor control and the other end, by means of a spring link, 
is attached to the tiller. 

When a movement of the telemotor takes place the spindles of the pump are moved. The pump at 
once draws oi! from one pair of cylinders and discharges into the other pair, thus moving the rams and 
the tiller. This moves the end of the floating lever which is connected to the tiller and the pump spindles 
are returned to the position at which the pump ceases to deliver oil and the rudder stays in this position 
until the telemotor is again moved. 

If the spindles are moved in the opposite direction, a corresponding operation takes place, moving 
the rams in the reverse direction. 

The safety devices fitted to the gear are numerous. 

A bye pass is provided joining the two cylinders of one set and spring loaded shock valves are fitted 
in this line. These shock valves are set to lift should the pressure on the cylinders, due to a heavy blow 
on the rudder, exceed the ordinary working pressure by about 10%. The rudder thus gives way and the 
tiller moves the spindles controlling the pump and puts the pump on stroke, returning the rudder to its 
original position. This device prevents an abnormal stress on the rudder stock. 

A replenishing tank, connected to both pumps, and fitted with non-return suction valves on each 
line, is provided for automatically making up any leakage in the system. Air cocks are fitted on all 
hydraulic cylinders. 

By means of hand-operated valves, the connections from the valve blocks to either pump can be 
isolated without interfering with the working of the other pump. Stop valves are also provided at each 
of the hydraulic cylinders, so that either pair of cylinders can be cut out without interfering with the 
working of the other pair of cylinders. 

The reserve pumping unit can be brought into action instantaneously by starting the motor of the 
stand-by pump. It can be seen that these arrangements meet any circumstances which might arise and 
that this is probably the best and safest type of gear which can be fitted. It should be noted that where 
two independent sets of rams and cylinders are fitted, operated by separate pumps and motors, as is usual 
in the four ram gear, it is not required that an additional means of steering be provided. 

Where, however, the tiller is operated by a single set of rams, controlled by one pumping system, an 
auxiliary means of steering will be required, but, if operated by two independant sets of pumps, no 


21 


additional means need be provided. The additional means of steering may take the form of a small 
quadrant bolted to a tiller, keyed to the rudder stock and extending aft. The quadrant is operated from 
the deck above by means of a pinion wheel, keyed to a shaft on which a handwheel is fitted. The hand- 
wheel thus controls the rudder, entirely independent of the electro hydraulic gear. An alternative 
arrangement of secondary means of steering is by means of blocks and tackle in conjunction ad: a 
separate tiller, keyed to the rudder stock, but this method is very rarely resorted to in this type of gea 


In connection with the arrangement of gear with two pumping sets, operated by alia ate Ease 
and four rams, which does not require a secondary means of steering, it is the usual practice in cases 
of this kind for the cables serving one of the motors to be led through the tunnel and those for the 
other motor through the after hold or on deck. 

The arrangements of these cables is left to the discretion of the owners and builders and in some 
cases the cables for both motors are carried in one group from the engine room amidships to the aft 
steering gear. In a case of this kind there is every liklihood of a damage to one set of cables also 
putting the other set out of action, thus stopping both motors and, al ome stroke, the main and 
auxiliary gears cease to function. 

It would appear that, for this portion of the gear to be of the same standard of efficiency as the 
remainder, two entirely separate leads of cables should be provided. 

The variable delivery oil pumps are of two types, each fulfilling the same function in a different 
manner, 

A sketch showing one type is shown in Fig. 13. 

The pump consists of a main cylinder body in which are formed a number of radial cylinders which 
terminate in a bronze bush. The bush rotates round a fixed main shaft in which is the central valve 
with suction and delivery ports. The outer ends of the plungers are attached to slippers, which run in 
an outer ring which is mounted on ball bearings. Pipes are ted from the valve ports to the hydraulic 
cylinders of the steering gear. The floating ring bearings are carried on guides which can be slid 
horizontally in a direction at right angles to the main drive and the control of this sliding motion is 
carrried out by the telemotor. 

When the centre of the circular path of the slippers coincides with the centre of the main shaft, no 
radical motion is communicated to the plungers. Displacement of the centre of the floating ring from 
coincidence with the centre of the cylinder body causes the plungers to move im their cylinders thus 
sucking liquid through one port and delivering through the other, the amount of movement taking 
place being dependent on the extent of displacement. 

If the floating ring is moved in the opposite direction, what was previously the delivery port now 
hecomes the suction port. The flow of liquid is therefore reversed without alteration in the direction of 
rotation, In moving from the position of maximum delivery to one hydraulic cylinder, to maximum 
delivery to the other, the disch: wee is gradually reduced until at the centre position it ceases and then 
increases in the opposite direction. 

The movement of the telemotor displaces the floating ring and puts the pump on stroke, thus 
pumping liquid into one of the hydraulic cylinders and drawing from the other. This causes the tiller to 
move and, in so doing, the hunting gear Comes into action and the control spindle of the floating ring 
is returned to the no-stroke position, when the rudder corresponds with the degree of helm on the 
telemotor. 

An alternative type of pump fulfilling the same function has the cylinder body, as before, mounted 
on the main shaft. In this pump the cylinders are bored parallel with the main shaft and the cylinder 
barrel rotates in contact with a valve plate which is stationary. 


The pistons are connected to a socket ring which in turn is connected to the main shatt by a double 
universal joint. The socket ring rotates in a pivoted member which can be tilted and the greater the 
tilt, the greater the delivery due to increased travel of the pistons. When the socket ring is vertical, the 
pump is in the “no- stroke” position but any deviation from the vertical, causes suction through one of 
the valve ports and delivery through the other. Tilt in the opposite direction causes the flow of oil to 
reverse. 

The mechanism of the telemotor varies the tilt of the socket ring, thus controlling the rate and the 
direction of flow to the hydraulic cylinders. 


22 


It will be seen that both these types of oil pumps can be driven by unidirectional constant speed 
electric motors or direct coupled steam engines and fulfil their function of varying the angle of the rudder 
as desired. 

It should be pointed out that, due to the shortness of the tiller of the electro-hydraulic gear in 
comparison to the diameter of the quadrant of the ordinary steam gear, a greater force is necessary to 
turn the rudder. For this reason, special care should be taken with the fitting and riveting of the stools 
below the hydraulic cylinders, and the deck should be stiffened extensively. 


TruNK Piston Type. 

For vessels in which the space for the steering gear is limited, a type of electro-hydraulic gear has 
heen specially designed. This consists of two hydraulic cylinders, their centre lines being fore and aft. 
The rams are of the trunk piston type and the connecting rods are attached to the tiller by a crosshead 
pin, the other end of the connecting rod fitting into a shoe in the inner end of the ram, thus allowing the 
connecting rod to move angularly to suit the motion of the tiller. 


In other respects, this gear is the same as the electro-hydraulic gear already described, having either 
two pumping systems or one pumping system and a hand gear, worked from the deck above through a 
shaft and pinion geared to a quadrant, keyed to the rudder stock. 


ComBINED HANb-HypraAuLic AND ELEcTRO-HypDRAULIC GEAR. 


A development of the electro-hydraulic gear combined with hand-hydraulic gear has been evolved 
lately, primarily for use in small craft, when steering is effected by hand in the open sea and by power for 
harbour and dock work.. 


The new gear consists of a variable-stroke pump which can be driven either by a continuously running 
electric motor or directly from the steering wheel by means of a chain drive, the alteration from hand to 
power steering being carried out by movement of a lever on the pump. 


The power unit and pump are situated on the bridge and the connection to the horizontally opposed 
hydraulic cylinders operating the tiller is by two small pipes, carrying the oil. 


When power steering is used, the pump is connected to the electric motor by a clutch, and the 
mechanism of the pump is controlled by a horizontal lever on a pedestal which puts stroke on the pump 
by manipulation of the control spindles, as already descrilid. As soon as the rudder takes up the 
desired position, a rudder indicator on the bridge, driven from the rudder, shows this new position and 
the controlling lever is released, the pump springs back to the no-stroke position and the rudder stays at 
this angle until a further movement of the lever is made. 

When hand steering is employed, the electric motor is cut out and a lever on the pump moves the 
control spindle so that the pump is in the full-stroke position. It then becomes a reversible pump, driven 
by the chain drive direct from the steering wheel, the direction of rotation of the hand wheel determining 
which side of the pump is delivery and which suction. The advantage of this type of gear, which is 
only suitable for small craft, is that the power unit of the gear is always under the control and in the 
sight of the helmsman, who can alter the gear from power to hand drive or vice versa, by the movement 
of a change over cock. 

It should be noted that this arrangement of hand and power steering does not constitute two 
entirely independent means of steering, as the same pumping system is used in each case, and a 
secondary means of steering would require to be provided. 

Several arrangements of steering gears working on the same basic principles as that described have 
been produced lately, and full information concerning their design and manufacture have been published 
in the technical press. 

With regard to this type of gear, it has been mentioned that on one occasion, when the motor on the 
bridge was started up. during trials, the compass was very materially affected, and a second compass was 
provided abaft the funnel and the use of the electric motor was confined as much as possible to going up 
and down rivers, where the captain could see his objective. 

As it was stated at the time by the makers of the gear, that this was their first experience of this 
effect, it would be of interest to know if this case was unique or if similar instances have been noticed. 


STEAM-HyDRAULIC STEERING GEAR. 
This gear is of the same type as the electro-hydraulic gear previously mentioned, with either two 
or four rams working in a corresponding number of cylinders, the difference being that the motive power 
is supplied by a twin cylinder steam engine instead of the more common electric motor. 


It has been designed for use in vessels with steam auxiliaries to take the place of the older type of 
steam gear. 


The control valve of the steam engine is operated from the bridge by a telemotor. When the 
wheel on the bridge is moved, the telemotor in the steering compartment opens the control valve and 
admits steam to the engine, at the same time controlling the direction of flow of the oil from the pump. 


When the rudder corresponds to the handwheel position, the engine is so adjusted that it idles at low 
speed. ‘The advantage claimed is that, as the engine is unidirectional, it saves the loss of steam inherent 
with a reversing control valve. 

This is particularly important in vessels in which the auxiliaries depend for their steam supply on an 
exhaust heat boiler. 

In the two ram gear a spare tiller is fitted to the rudder stock for use with relieving tackle as ¢ 
secondary means of steering. 


ELECTRIC STEERING GEAR. 
In conclusion, this paper would not be complete without some reference to the latest developments 
in electric steering gears. 
The two main types are Ward-Leonard and single motor, the difference being in the supply and 
control of the current to the motor. 


In each case the gear consists of a spring-harnessed toothed quadrant and tiller, similar to that 
employed in a direct acting Wilson-Pirrie steam gear, the motive power being provided by an electric motor. 


The motor drives a worm gearing, which in turn drives a pinion geared to the toothed quadrant. 
As an auxiliary means of steering, a hand gear is provided, driving through a pinion to an auxiliary 
quadrant keyed direct to the rudder post. 


As the subject matter of this paper is of interest to both ship and engineer surveyors on both the 
inside and the outside staffs, it is hoped that as many as possible will enter into the discussion, so that 
a representative body of opinion can be obtained regarding the different types of steering gears at 
present installed, especially as regards the rod and chain gear, about whic h there has been so much 
comment lately. 


Finally I would like to thank the firms who have given me information and literature. Also 
J. N. Buchanan, Esq., for his comments and perusal of the paper and W. J. Paulin, Esq., for his 
information and a copy of his paper ‘* Modern Practice in Ship’s Steering Gears,” an extract from which 
appears to be a fitting conclusion to this paper. 


COMPARATIVE PRICES. 
The following list gives comparative prices for different types of steering gear. For convenience a 
basis number of 100 is given to the midship chain steam gear, the other gears being given numbers 
valculated from this basis. The figures are not in anys standard units of price, being only a guide for 


“0 arison. 
comparison Comparative 


Price Figure. 


Midship chain, steam driven gear with twin drums shafting control... ceo AKOY6) 
Wilson-Pirrie steam ge ar, telemotor controlled including telemotor Sch ee 207 
Single motor, all-electric Wilson-Pirrie type gear, multi core controlled ee 2 


Ward-Leonard, all- elec tric Wilson-Pirrie type gear, Wheatstone Bridge control 330 
Electro-hydraulie gear, telemotor controlled —... xe ne) 1 Ade oe ETH) 


QUADRANT 


FOR ROD & CHAIN GEAR. 


QUADRANT 8055 KEYED & 


SHRUNK TO RUODER STOCK 


ToP BAR G++ 30 cea 


OER STOCK 


Ruoose® stocK 10 Dian 


10's @ « 1% DIAM 


QNE LONG LINK 


FORGED IRON QUADRANT 


DECK STOPS 
To se Fitted 


Kia. 2 SPRING-HARNESSED QUADRANT. 


d+ ROD DIAM® 
A? ad 
> lAd 
C+ ad 
Er ie 
Et lka 
Fre 2ha 
Rtild 


CONNECTING LINKS. SHACKLES 


g 


eT iN I al 
at ees Wi 


SLELSS SS Km 


i 
S 


S 


STRETCHING SCREWS. 


®, 
ONE LEFT HAND & 
ONE RIGHT HAND 


HITWORTH THREAD 


= ee 20°8 


3 = Stasin's 


g10e View 


PaTen® FRE TION ROODER BSRAce 


PACK Vil pRiCTION BRAKE (3) 


. Sy 
SS 
SS) 


PATENT FRICTION RUDDER BRAKE (2 


“7 Position OF Wine 
so Wat MET WARD OVER. 


secu QIGnus wile 
WASHER 
FRICTION BRAKE (4) 


boi 


WOOD CROCK 


’ 
4 & 
¥, 

y 5 
v - 


4 


FILLING PLUG 


iced ia) 
SSS 


eer) 2 00 


PATENT HYDRAULIC RUDD: 


BRAKE (i) 


PATENT WYDRAULIC RUDDER BRAKE 


AUXILIARY “STEERING GERI 
PLAN VIEW 


HYDRAULIC RUDDER BRAKE (3) 


Fie. 6. 


SINGLE BLOCK 
SE eee 


ROPE RELIEVING 
TACKLE 


AUXILIARY MEANS 
OF STEERING 


CHAINS 15/6 DIAM 
PROOF TEST 315/a Tons 
/ . BREAKING TEST G3% TONS 


‘Me SUMCKLE 7 LOAD + 6 35 TONS 


DECK F ry : 5 OECK FITTING. 6-7 RIS Pu. OF WINCe 
wuss 13 LoaO = 3 12 SINGLE IRON BLOCK [Cono 15 75 TON 32 TONS 
Lgn0 635 1G ] /p ton GBs tons | ne 22 —ens 
tear / 2'2 GESW Rope 
io SYMCKLE ome ————— 
LORO !2 7 Tons aS io SHNCKLE LOAD 15-75 TONS 
p \4 DOUBLE IRON BLocK 12, DOUBLE IRON BLOCK 
LOAD 12 7 Ton’ LOAO 15.75 Tons 


RECOMMENDATION OF STEERING GEAR COMMITTEE 
SPRING 2/4 SQUARE LOAD |2-7 Tons 


Olam] oF Rue 
QUADRANT 8-0" 


ten st eee 


RUDDER STOCK IZ DIAM 


BREAKING OAD OF AUXY GEAR *-G3% Tons ' 

BREAKING LOAD oF EACH WIRE * 127 TONS | 
27 22GF#SW ROPE | 
cane taco eecciomnioae 


Lebal 


Fic. 8. 


BRITISH ENGINEERING STANDARDS ASSOCIATION 


HAND _ SCREW (AFT) STEERING GEAR. 


TWO HANOWMEELS 


. THE CROSSHEAD SHALL BE OF CAST oR WROUGHT STEEL OR OF NROUGHT IRON 
2. THE SCREN SPINDLE & CONNECTING 2005 SHALL BE OF ANROUGHT [RON OR WROUGHT STEEL 

3. THE SCREW THREADS SHALL BE OCF SQUARE TYPE & SHALL SE RIGHT-L LEFT HANDED AS REQUIRED 
4. No BUSHING 1s REQUIRED FOR THIS TYPE OF STEERING GEAR 


i 


Fig. 9. 


GsGs 75 BEVELED TD 


4 


2’: 


: Ri 
(eset \ 
== ee 


Sroumne ULL) Q LePet 


H (wwrwn) 


ELEVATION. 


QUARTER BLOCKS. 


Fig. 10. 


PLAN 


VIEW 


H FILTER 
H_REPLENISHING TANK 
fr fi 


p CTION & RELI ty 
ty FOR REPLENISHING SISTEM 


—s 


HAND OPERATED SHUT OFF 
Xb EY. iE 
HARG! TE 


HON! Pass 
VOevi AT Side 


id PION SHAST 


TELEMOTOR 


PLP INNECTION 70 
BOTTOM OF CYLINDER 


SECTION THROUGH TRANSMITTER 


SIDE ELEVATION 


CiRCuIy PIPES 


= aS 


HYORAULIC STEERING 


To CHARGING 
QF TRANSMITTER TANK 


CASTE SPATE NUT 
MAIN CROSSHEA 


AiR VALVE 
RECEIVER 


CYLINDER’ 
SPRING 


CHARG NG PIPES 


SN ed 
= es SS es 
Se LE 
joni L TRL en LWW 


HAND OPERATED BYE PASS YALYES 
COMIBINEO WITH SHOCK VALYES 


VALYES for 
ISOLATING CYLINDERS 


SE: 
OOS 
C 


p Pfr Spar 
(oe Reanavngeel 
0 UU rg. | 


he SY aC = 
+ Ae : ae |= 1S 


a eee 
YALVE BLOCKS 


rv 
eee 


Dy 


wes! Ss Oe I tHE, 


Fie. 12. 


DIAGRAMMATIC SECTION THROUGH CENTRE oF PUMP 


HEWING ALTERATION OF PATH OF GUDGEONS ENABLING 
PUMP To SUCK & DISCHARGE Liauvid THOUGH CENTRAL VALVES 


PUMP_IOLING PIMP_ON STROKE 


PATH OF SLIPPERS 


& 


be A 
isvcsskeest LLL 


LONGITUDINAL SECTION TRANSVERSE SECTION 
VARIABLE DELIVERY PUMP 


DISCUSSION ON Mr. G. BUCHANAN’S PAPER 


ON 


STEERING GEAR. 


W. THOMSON. 


Mr. President and Gentlemen, I think the subject of this paper is essentially a topical one in these 
days, and I am sure we are all much indebted to Mr. Buchanan for the excellent description he has given 
of the various forms of steering gear and the merits of each. 

This question of steering gear has been very much in the public eye, on account of one or tivo 
spectacular losses of ships attributed to failure of steering gear, but, as pointed out by Mr. Buchanan, 
out of 10,000 casualties reported in the public press in one year only 70 are in any way related to 
steering gears. 

In order to get some idea of the relevant importance of this, | looked up an investigation made in 
this office some time ago about the recorded cases of fires on board ships, and I found in a year we had 
700 cases of casualty due to fires—about ten times as many cases as have been attributed to steering gears. 


A little reflection on these figures will show that steering gear failures are only a minor cause 
of loss. 

When we come to consider hand steering gears—the hand steering gear nowadays is only fitted as a 
secondary means of steering—from what I have been able to make out from my investigations into the 
subject, this hand steering gear is not nearly strong enough, The scantlings are far too light. That is 
a relatively minor point when we come to the ordinary rod and chain gear. I suppose this must have 
been the earliest type of steering gear, and it has been continually improved for many years past, and 
to-day 1 think it does not merit all the stones which are thrown at it. 

| have examined the survey reports in this office for the past eighteen months in which reference has 
been made to casualties to rod and chain gear. There are some points reported such as a broken 
steering rod, a loose quadrant, a case where the deck was stated to have fractured, but 90 per cent of the 
s reported were related to the chain or to the pins in the guide blocks. 


My experience of practical survey work is very limited, but it seems to me there is no difficulty in 
examining these items. 

I think we might say that the rod and chain gear as at present fitted is reasonably satisfactory. 
That is no reason why we might not try to improve it, and | think Mr. Buchanan has shown the lines on 
which some improvement might be sought. 


K. Porrs. 

We have to thank Mr. Buchanan for a very detailed paper on a subject which has recently been 
much to the fore, due to the report of the Steering Gear Committee. His paper represents a collection 
of most useful information, but, as such, does not present much opportunity for discussion, but I should 
like to mention one or two points. 


= 


For obvious reasons Mr. Buchanan does not suggest a preference for any of the types of gears he 
describes. He states that the most vulnerable is the rod and chain type. I would suggest, however, that 
although there has been considerable discussion about it the failures of such gears have been relatively 
few, and that the failures were not due to the gear itself but to lack of care and supervision, primarily on 
the part of the ship’s personnel. I agree, however, that sometimes wear and tear is not readily detected, 
particularly on the steering chains. For instance, I had an opportunity recently of seeing some links 
taken from a vessel. The links when “in situ’ were apparently all right, but when they were cleaned 
and up-ended they were found to be deeply grooved to a rather alarming extent. 


Mr. Buchanan mentions the alternative of fitting the steering gear aft and adopting what he terms 
the ideal arrangement of leading the steam pipes along the tunnel. One owner I met some time ago used 
an entirely different word to ‘ ideal” in regard to this arrangement. Apparently he was somewhat 
prejudiced, for he stated that, in one of his vessels in which it had been adopted, cargo had been damaged 
due to the heat from the steam pipes in the tunnel. I suggested to him that this would not have occurred 
if the pipes had been properly insulated, and I might add that this is now a requirement of the Rules. 
He thereupon brought up the second point mentioned by Mr. Buchanan that, due to the distance from 
the engine room to the steering gear house, the steering engine does not get the attention it should, even 
if there is a tunnel escape leading to the house. 


Tho author deals with an objectionable feature in respect of the ordinary type of right and left 
hand screw gear, that is the absence of shock absorbing arrangements. There are several cases where 
this type of gear has been put out of action due to this, and the methods suggested by Mr. Buchanan for 
dealing with this matter are much to be advocated. Further, the usefulness of this gear is definitely 
limited, and one must agree with the recommendations of the Steering Gear Committee that it should 
not be fitted in large cargo vessels. 


A sketch is given in Fig. 1 of an ordinary quadrant and in regard to this I might mention one point 
that might be useful. It has been pointed out to me on more than one occasion that the Rules do not 
specify the thickness of quadrant plates and it would be helpful if some guidance on the matter were 
given. I would suggest the following basis as providing a minimum standard :— 


The thickness of the plate to be the Rule radius of the quadrant expressed in decimals of an inch, 
e.g., for a 6 in. diameter rudder head the quadrant radius is 4 ft., therefore the plate should be “40 in 
thickness, and for an 8 in. diameter rudder head the radius is 4 ft. 6 ins. and the plate should be -45 in 
thickness. This basis would agree with the thickness given by Mr. Buchanan in his sketch where the 
diameter of the head is 10 ins. and the plate 2 in. as against °60 under the suggested basis. 


L. H. F. Young. 

The rod and chain steering gear is undoubtedly the one that has given rise to more controversy 
than all other types. It is certainly open to more damage than the others, but as the author points out, 
although the cases of damage are numerous, the percentage is relatively small. Whatever the past 
evidence may have been as to its vulnerability, it is quite obvious from the consideration given to it by 
the Steering Gear Committee, and from the numerous recommendations made, that it is regarded with a 
certain degree of suspicion. Its low initial cost is its attraction to shipowners, but this is offset in some 
measure by the repairs necessary to maintain it in good condition and by its low mechanical efficiency. 

The steam tiller is a type that used to be in considerable favour some years ago. It is a gear that 


has proved most reliable in spite of its apparent clumsiness and the fact of the engine not being on a 
fixed bed. 


A new type of gear is referred to at the bottom of page 16, ‘This type seems to entail rather a lot 
of gearing as there are three lines of shafting. A simpler form is that used in many warships, where the 
steering engine is fixed high up on the after bulkhead in the engine room and a straight line of shafting 
led through to the steering gear flat. This, however, would not be suitable for all types of merchant 
vessels, as the shafting must always be in an accessible position. 

Passing now to the electric-hydraulic gear, this is one which has gained great favour in recent years 
in spite of its initial cost. It is by far the smoothest and quietest in operation. As the author points 
out, however, it imposes heavy stresses in the structure on account of the shortness of the tiller. 


It may be noted that the shock produced by a sea striking the rudder is relieved by means of relief 
valves in communication with the hydraulic cylinders ; but it is open to question to what extent this 
provides adequate cushioning. A relief valve capable of dealing satisfactorily with a sudden blow on the 
rudder would need to be fitted direct on to the hydraulic cylinder and to have an area much greater than 
that of the delivery pipe. Would a better effect be produced by fitting all four hydraulic cylinders with 
air vessels? Or would such an arrangement impair the steering qualities ; for it would be an essential 
condition that the quantity of air in each air vessel would have to be maintained constant ? 

Further, if it is considered that the cushioning properties of this gear are somewhat low, has 
consideration been given to the question of increasing the scantlings of the rudder stock above what 
would be required for a quadrant type of gear? Whatever importance may be attached to these various 
points, however, the electric-hydraulic gear has for many years now given good proof of its reliability and 
performance, so that it rather points to the fact that very little provision need be made for absorbing shock. 


The Rules require two independent means of steering and the usual arrangement of electro-hydraulic 
gear provides for this. This can hardly be said to be fully complied with unless the leads of the two sets 
of electric cables are remote from each other. The author makes an important point of this; but 
unfortunately such an arrangement is by no means universal. 

A case may be quoted where the two sets of cables were grouped together, and a fire occurred in one 
compartment putting all the cables out of action. When permanent repairs were carried out, one set of 
cables were led under the upper deck at the port side and the other set under the second deck on the 
starboard side. Such an arrangement might with advantage apply to the telemotor transmission pipes, 
for it is quite easy for these to receive damage. But there are not many vessels that even have dual 
sets of piping. 


J. R. BreverRtper. 


It is stated in the paper that out of 334 cases of damage reported from February, 1926, to December, 
1935, 219 cases related to rod and chain gear, that is, 65°5 per cent, and that only 0:7 per cent of the 
10,000 casualties reported in one year were due to steering gears. Assuming the figures just quoted, 
0-46 per cent of the casualties will have been due to steering gears of rod and chain type : an apparently 
insignificant figure. 

But surely the use of mere figures hardly suffices to give us the proper perspective. The true 
assessment of the figures lies in the consequences arising from the casualties. Ships and their cargoes can 
be replaced in the event of loss, but the lives of the crew are irrecoverable. In such circumstances it is a 
pity that the rod and chain type of steering gear cannot be abolished in favour of the more efficient and 
more reliable gear situated at the rudder head. 


No doubt this statement can be refuted by countless examples of rod and chain steering gears which 
have given faithful and trouble-free service but there must always be misgivings about this type of gear 
so long as the deck rods and chains are at the mercy of deck cargoes, which are by no means ** tenants 
fixtures” when the vessel is in a gale, however disrespectful this behaviour of the cargo may be to the 
freeboard regulations. 

Further, the chains, rods and sheaves are liable to neglect, and to suffer from unskilled attention from 
the deck department, a disadvantage which more than equals the alleged lack of attention given to steering 
gears situated aft. Actually the steam steeriug gear of an ocean going vessel is usually the least trouble- 
some bit of mechanism on board, it is usually generously proportioned as regards bearing surfaces, and the 
lubricating arrangements are such that it need not be inspected at frequent intervals, nor need it be 
inaccessible when fitted aft. If an escape trunk be led from the tunnel to the steering gear house, so that 
the greaser may include it in its rounds without going on deck. 

The difference in cost of the two types of gears under consideration is an insignificant percentage of 
the cost of the vessel, especially so in modern steamers, where the cruiser stern already provides the 
necessary housing. ‘The question of the vulnerability of the control gear and steam supply pipe to the 
aft steering gear need not arise, if as suggested in the paper, the controls and steam pipe be led along the 
tunnel. In any case it is an uneconomical proposition to keep steam on deck for the purpose of supplying 
the steering engine. 


4 


It is noted that a gear has been devised in which the engine is connected to the rudder head by shafting in 
the tunnel, and thence by gearing and shafting up a trunkway. Such an arrangement is, at the best, a 
compromise, and the advantages do not appear to be worth the extra trouble and complication. To revert 
to the older type of gear, it is regretted that the fitting of brass bushes and the provision of grease cups of 
adequate capacity were not made compulsory in the case of the deck sheaves for the chains. 


With reference to the fitting of keys to the rudder stocks, it is not uncommon to see the key ways 
distorted as mentioned. At the same time it is no compliment to the shipyard fitters that the efficiency 
of the connection should rest solely on the key. 


In contrast it may be mentioned that many engine builders now prefer to omit dowels in crank shafts, 
since they can rely solely upon the shrinkage of the web on the shaft. Apparently this confidence would be 
misplaced in the case of rudder quadrants. The auxiliary means of steering appears to be unsatisfactory 
and one cannot help thinking that the use of hydraulic steering gears of two unit construction is the best 
solution of the difficulty. 


If chains are to be regarded as part of the steering gear, there is no reason why they should not be 
regarded as of equal importance as anchor cables or even of greater importance since the steering chain is 
not in duplicate. Accordingly it is good to note that the Steering Gear Committee have recommended 
that a spare length of chain be supplied. This will allow the old chain to be repaired, if necessary, at a 
port where proper facilities are provided for testing the chain to discover the merits or otherwise of 
the repairs. 

In conclusion, I wish to thank Mr. Buchanan for a very interesting paper. 


J. ANDERSON. 


The author deserves our congratulations in his choice of subjects and for the thorough and 
interesting manner in which he has treated it. 


In reading this paper the following points appear to call for some comments. 
gs i g I PI 


Despite the author’s impartial examination of the rod and chain type of steering gear and his 
remarks on its merits and demerits, the fact remains that cheapness is its only attractive feature. 
Steering gears demand reliability in operation, hence simplicity in design and lay-out and the obvious 
arrangement is to place the prime mover near the quadrant and thus eliminate all potential sources of 
trouble. 


The statement that the full shock on the rudder is taken by the length of chain between the 
quadrant and the buffer spring, without any relief, is hardly correct. This length of chain takes the 
same load, a function of the compression on the spring, as that taken by the rods and chain forward of 
the spring, plus a small load necessary to overcome the inertia of the chain. 


An interesting point is raised in a suggestion that the maximum load on the gear is produced by the 
steering engine or motor. This depends on the type of gear employed and in the case of hydraulic gears 
is probably correct, within certain limits. With mechanical gear of the ordinary type where the steering 
engine drives the chain drum through a worm wheel, the slow pitch of the screw prevents the wheel 
turning the worm, so that the gear at this point is fixed to any load coming from the quadrant side. In 
this case, the load on the gear resulting from a heavy sea striking the*rudder might easily exceed that 
produced by the engine. 


> 


From details shown in Fig. 3 which, it is assumed, are as recommended by the Steering Gear 
Committee, it is noted that the bolt in the fork is parallel. In making this connection the jaws of the 
fork are drawn down hard on the eye by the bolt and the hinged joint is rendered ineffective. Further, 
where there is excessive clearance between the eye and the fork, the jaws of the fork are bent inwards 
when tightening up the bolt resulting in the neck of the fork being severely stressed, Fractures are 
frequently found at the forked ends. 

It is suggested that the body of the bolt should be enlarged so that it can be hardened up and grip 
one jaw only, thus leaving the fork and eye free. 

Those remarks apply to the link in Fig. 3 and to the quarter block, left, Fig. 10. 


Referring to the quarter blocks shown in Fig. 10 the one to the right has many good features, 
including a large pin with generous bearing surface and the means for effective lubrication. The block 
on the left has a portion of the housing cut away to clear the chain, surely this can be avoided by 
swinging the block round to a position more or less in line with the resultant force. 


The author’s full treatment of the subject leaves little further to say except to offer him our thanks 
for his informative contribution to the records of the Staff Association. 


E. W. BiocksipGE. 


My first observation regarding the subject under discussion is to congratulate Mr. Buchanan on his 
method of presenting the paper by narrowing down the sections dealing with the different types of 
steering gear within limits which permit members to grasp the essentials rapidly without investigating 
many details. The sketches associated with the paper are excellent and enable one to read the reports of 
the Steering Gear Committee with greater intelligence and ease. 

The author on page 2 gives certain statistics relating to the percentage of casualties at sea as a result 
of defective steering gear. Too much importance is given to statistics, and my own personal opinion is 
they often lead to wrong conclusions. If you compare the cases of damage to steering gear which are 
considered to come within the category of major casualties with other cases of casualty of similar 
magnitude the percentage for steering gear failures would be increased alarmingly, but the evidence is 
misleading. 

There appears to be an undercurrent of thought, expressed sometimes in Courts of Enquiry into the 
loss of ships, against the efficiency of the rod and chain gear which is the most common type of steering 
apparatus fitted on cargo vessels. The drawback to this type of gear is the frequency of damage caused 
by the absence of efficient means of protection in way of the hatchways and particularly on those ships 
engaged in the coasting trade. 


The facilities provided at some of the ports of call for loading vessels are so crude, and the cargoes 
carried are so varied, the steering rods and chains often come in for bad treatment. The need for a 
closer supervision and a keener oversight on the part of the owner and his employees is now becoming 
more apparent. 

The Convention Load Line Regulations call for effective protection of the steering gear leads on 
ships when employed in carrying timber deck cargces, and, as far as practicable, they shall be accessible. 
It is a simple matter making provision for the protection of the leads, but I suggest it is not within the 
limits of ordinary practice to arrange for accessibility hence the necessity for an efficient secondary means 
of steering. 

In this connection I would suggest from my limited experience with the use of the block and tackle 
arrangement in association with the winch, that it is not possible to steer the ship effectively, and its use ‘ 
is only sufficient to keep the head of the ship into aseaway. Subject to there being a sufficient number of 
deck hands available, the hand steering gear is more efficient. 

I would like to ask Mr. Buchanan to state, in the event of a complete breakdown in the main steering 
arrangements, What arrangements are provided for holding the rudder in position pending the tedious 
change over to the secondary means of steering by blocks and tackle. 

The information placed at the disposal of the surveyor for dealing with the upkeep of and repairs to 
the steering gear apparatus is and has been very meagre. The paper under discussion, will therefore, be 
welcomed by the outport members. 

The Society’s rules limit the application of hand-operated steering gears to vessels under 
250 feet in length, but I feel very doubtful whether a hand-operated steering gear is sufficient for the needs of 
a steamer 200 feet in length, having in view the limited number of crew available and the advance made 
in speed and other characteristics of the modern cargo ship. 

The Board of Trade regulations are limited in their application to ships holding St 1, St 2 and St 3 
passenger certificates, and cargo and ships holding other types of passenger certificates are not referred to. 
It would appear, therefore, that the present rules for the guidance of surveyors should be amplified to suit 
modern conditions under which surveys are carried out. 


6 


C. H. Srocks. 


We are indebted to the author for a very interesting paper on a most important part of the ship’s 
equipment; it is opportune to review the position in the light of the findings of the Steering Gear 
Committee. 


As is usual when a public inquiry is called there was a prior flood of scare suggestions—uninformed 
opinion—but no “inquest” was held on the rod and chain type of gear; it will continue to give years of 
satisfactory service provided it receives proper attention. 


All officially accepted forms of steering gear are good, some have particular merit for special 
circumstances and none are foolproof but their very efficiency has perhaps induced a slackening of 
between—survey attention. 


It has been apparent for some time that, in matters of detail and routine examination, there was 
room for improvement to consolidate good practice, even to harmonise in scantlings some of the dependent 
fittings so that—at least in theory—all component parts might take an even strain. It is not necessary to 
admit that there were points of relative weakness since the conditions of stress are ill defined and margins 
are only comparative. In this connection, the author’s use of the term “ factor of safety” is open 


to question since it suggests a knowledge of fact which does not exist. 


No more can be said than that the transmission gear throughout its length must be properly 
proportioned to the diameter of the rudder head which, in turn, has due regard for factors which do not 
appear in theoretical formule—there is no stress basis. For this reason it would be a mistake to suggest 
factors of safety or to make the gear stronger than the rudder head ; always the relatively weak member 
should remain in the transmission so that if something must break under stress of weather, it won't be 
the rudder. Difficult as it may be to effect temporary repairs to the main gear or to rig the emergency 
gear it is even more difficult to improvise a rudder. 


A point not fully dealt with is the time factor. The Society’s Rules define the power in terms of 
speed in operation, hard aport and hard astarboard, but an excess of power is not desirable. To have 
power sufficient to swing the rudder full over in double quick time will in itself cause undue stress. 
particularly under circumstances when it may be used, as in putting the ship about in the face of 
exceptional weather. The possibility rather suggests a governor control on power units which exceed 
the Society’s requirements. 


The chief difficulties are centred around the distance which exists between the rudder and the point 
of control and each method of transmission has its own particular appeal, its advantages and_ its 
disadvantages. The rod and chain type has one important difference which may explain unsuspected 
weakness showing up at critical times. In the assembled state there is no adequate test in port whereas 
steam pipes, telemotor gear and electric wiring can be submitted to an overload test in port to ensure that 
they are in good order. This disadvantage might be overcome by a quayside test on the chains, rods, etc., 
by working the gear with the rudder locked, but such a test would be inadvisable without safe control of 
the power applied. 


Chains, rods, etc., are usually accessible and are easy of repair—a spare length of chain can be 
substituted for a broken rod. Steam pipes are liable to damage and, in carrying considerable pressure 
are not always amenable to temporary repair, also there are appreciable heat losses in a long lead of steam 
pipes and active corrosion in the surrounding structure. The advantage of placing electric leads well out 
of harm’s way, possibly through ‘tween decks may render them not always accessible and they introduce 
the risk of fire. 


So far as the rod and chain type of gear is concerned, the practice of carrying a sufficiency of spares, 
routine interchange with spares and careful examination of the parts removed before they in turn are 
considered as spares. cannot be improved upon. With the better facilities for check in port on other 
forms of gear, there is less occasion for worry, particularly if the gear is situated well within the strength 
structure and not within a deckhouse on the poop deck, susceptible to damage from following seas—one 
case is in mind in which the house partially collapsed over the gear and all but put out of action not 
only the main gear but also-the emergency gear. 


On the subject of shock absorption and the difficulty to determine a working tension so as to leave 
sufficient margin for shock, it might be well to adopt two sets of compression devices, working. in 
sequence—one operating below the proof load of the chain as for ordinary working conditions and the 
other operating only above that value for exceptional shock. In this connection it is well to remember 
that we are dealing with live loads considerably augmented if there is any initial slackness. There is 
evidence that buffer springs do sometimes close up and bye-pass the shock. Contrary to all argument 
that chains should have an initial tension is the claim that the helmsman gets the feel of steerage way 
better and steering is easier when chains are slack. Be that as it may it sheds light on undue wear and 
some of the subsequent damage. 

Under the heading of quadrants, the author makes out a case for fitting runners to carry the weight 
of the quadrant, etc., but, to be effective, they would require to be rarefully fitted ; also they imply 
frequent adjustment for wear down in the rudder carrier to obviate the weight of rudder being transferred 
to these runners and upset of alignment. A particular case of difficulty in steering was associated with 
misalignment due to excessive buoyancy in a hollow rudder—the whole rudder rose and fell quite an 
appreciable amount on passing Waves. 

Under the paragraph on brakes, it was well to include the slot and pin type if only—as the author 
indicates—for the purpose of stating that no fitment ever had less resemblance to a brake. 


S. T. BrRYDEN. 


Mr. Buchanan’s paper has satisfied a long-felt need, and I am sure we are all grateful to him for this 
very complete paper on steering gears. 

It would be difficult to offer any criticism on the paper beyond a reference to Fig. 1 in which the key 
appears to have been driven in from the bottom of the quadrant instead of from the top. 


I would, however, venture to state that the retention in modern ships (of all but those of moderate 
size) of so effete a survival as the rod and chain type of steering gear seems to be a most lamentable 
example of the victory of parsimony over efficiency. It would be difficult to discover any machine more 
mechanically inefficient with its large number of frictional parts, or any comparatively delicate yet vitally 
important ship fitting more liable to heavy weather damage through exposure. 

Mr. Buchanan shows that the percentage of total casualties over a period relating to steering gears is 
a very small one, but I should like to ask him in what percentages of total losses the cause has been either 
proved or surmised to be attributable to steering gear damage or defects. 


T. SHILSTON. 


It is mentioned on page 16 that the Steering Gear Committee recommends that steering chains 
shall be renewed when the effective area of the chain has been reduced by 15 per cent in the case 
of larger chains and 30 per cent in the case of small ones. [ don’t know whether this will alter the usual 
practice of condemning chains by eye and a piece of chalk, which method can be quite effective after a bit 
of experience. Perhaps the percentage reduction method will be less open to argument with hard case 
superintendent and will be more uniform in operation. 

Another point is the annealing of chains. As Mr. Buchanan states a common and bad practice is 
simply to pass the chains through a fire, and this certainly makes them easier of inspection. The task of 
getting repair yards to see the error of their ways in this direction is, like most education, a slow process 
but is a job that must be tackled. 

I rather question the real value of the auxiliary means of steering being dependent upon the after winch 
unless this winch has a substantial deck house built round it. The usual time for steering gear failures 
is in very bad weather and at this time the open deck is hardly habitable. 

The rudder brake is most important. I had the misfortune to serve on one ship—not classed with 
L..R.—where the steering chains broke in bad weather in the Bay. This ship had no rudder brake and 
there was a lot of perfectly good bad language wasted before the flying quadrant was caught. 


& 


Though the rod and chain gear is liable to many defects, the great majority of them are due to poor 
maintenance and if the gear is properly looked after it is agreed, I think, that it is quite reliable. This 
gear also has the advantage, in cases of ships with only one engineer on watch, of the engine being properly 
attended to which cannot be done when the engine is fitted aft. Where a ship is more fully manned, 
steering gear with the engine fitted at the rudder head is far more desirable. 


W. J. Roperts. 


We are indebted to Mr. Buchanan for his paper on a subject which is at the present time, thorny, to 
say the least. Our thanks are due to him for the comprehensive manner in which he has treated it. 


On page 7 the author mentions the practice of fitting long links at the ends of chain, and considers 
that such are hardly necessary, except where the chain is shackled to the quadrant. 


It would appear however, that, contrary to Mr. Buchanan’s statement, the inclusion of long links 
especially if the connecting links which he mentions are not supplied, is very desirable. The initial wear 
or “bedding in” of the links of a chain produces considerable elongation of the chain as a whole, and if 
bad weather is encountered soon after the new chain has been fitted, this elongation might take place in 
a comparatively short space of time, and might be of magnitude such that it could not be taken up by 
the Warwick screw. For instance, consider a length of 40 feet of 1 inch chain, in which each link wears 
40 x 12 

To—2 
elongation of the chain 10-9 ins., which is appreciably more than could be taken up by the Warwick 
screw. The elongation which would be produced by a number of links wearing until the maximum 
allowable reduction in area had been reached in each, would obviously be considerably above this figure. 
Therefore, since the shackle will not pass through the ordinary short link, long links should be fitted so 
that the chain can easily be shortened at sea by shackling the quadrant to the second or third long link. 
Further, since long chains will lengthen more than short ones for the same length of Warwick screw, it 
would appear to be desirable that the number of long links fitted should be proportionate to the length 
of chain. 


jy inch at the nip at each end. The number of links in the chain is = 174 and the consequent 


I should like to make an observation on one other item mentioned in the paper, namely, spring- 
harnessed quadrants. 


With this arrangement the whole weight of each spring, which will be very considerable in a large 
ship, is taken by forks which are bolted to the quadrant or tiller, and pass through the spring to the end 
plates. Due tothe continual movement in the spring, the end plates constantly work on the forks, and 
wear fairly quickly shows itself on the forks and in the holes through which they pass in the end plates. 


J. RANNIE. 


With reference to the sketch of an auxiliary gear arrangement, Fig. 8, may I ask the author if any 
particular advantage is gained by attaching the purchase and spring direct to the quadrant ? In the text 
he states that sometimes it is not possible to do this, and in these cases, it is necessary to supply a wire 
rope of sufficient strength to take the whole load. Admitting that the arrangement is a good one, from 
a mechanical point of view, in so far as it reduces the load as soon as possible, it cannot be overlooked that 
in the hypothetical case of both steering gear and brake failing, it would be a difficult, and very dangerous 
operation to connect direct to the quadrant a heavy spring, and a 14 in. double steel block with four parts 
of 24 in. wire passing through it, while the ship was tossing about and the quadrant was charging from 
side to side, whereas, except during a severe storm when this type of gear is next to useless, a 4} in. 
pendant could be shackled to the quadrant, led on deck and there made fast to the purchase. In other 
words, the arrangement shown makes the brake an even more vital factor and the author leaves us in no 
doubt as to his opinion on that matter. 


One further point, quoting from page 13. “The strength of the main gear is based on the designed 
speed of the vessel. The working conditions of the auxiliary gear are entirely different as it is not 
expected that any vessel will be driven at full speed when the auxiliary gear is in use and it is probable 


that the auxiliary gear will be used merely to keep the vessel head on to the seas. The weather conditions, 
however, will probably be severe and the force of heavy seas on the rudder bears very little relation to the 
speed of the vessel.” 

I do not quite understand what the author wishes to convey. It appears to me that, if the force of 
a heavy sea on the rudder bears very little relation to the speed of the vessel, once the auxiliary gear was 
rigged and working satisfactorily, provided the vessel was in open water and visibility good, there would 
be no necessity in the majority of cases for the vessel to slacken speed, as a few degrees of helm would be 
sufficient to keep the vessel on her course, said course perhaps having been altered a point to enable the 
vessel to ride the waves more comfortably. 


G. D. Rrrowi. 

I am sure you will agree that we have had a most excellent discussion on an exc:llent paper. 

Most of the things I had to say have been mentioned by other speakers, but nobody has referred to 
the important matter of steering gears with reference to the carriage of deck cargo. Looking at the 
thing in a narrow sort of way the use of rod and chain gears in such cases is a crime, but on the other hand 
we do know that the number of casualties from broken steering gears is comparatively small. Nevertheless 
it seems to me a very large addition to the actual sea-going risk to have a rod and chain gear in con- 
junction with a deck cargo. 


It is very well that people should know that in cases of major casualty at sea they are faced with a 
very close and stringent Inquiry. But in these days of intense publicity, of intense and hysterical 
advocacy by interested parties, care should be taken not to be forced into hasty, ill-considered legislation. 
I do not think this Society, at any rate, will ever be so stampeded. The public, through the popular 
press, are very likely to get hysterical when reading of sailors drowning at sea—much as we all deplore 
such happenings. There will always be accidents at sea—and we must not be unduly influenced by the 
fact that there are such accidents. That is not to say that efforts should be relaxed in the way of close 
supervision and in improving design and strength, but we have to face the fact that, so long as there are 
ships, there will be accidents. 


W. J. Crara (Newcastle). 


The rod and chain gear, as stated in the paper, is more liable to wear and tear and other damage than 
the other types of gear mentioned, and though the searchlight of criticism has been focussed on this 
type it is satisfactory to know that the percentage of defects is relatively small. 

The author raises a very pertinent question when he asks if it is possible that the practice of using 
the friction brake in heavy weather may be responsible for a number of broken chains, and it is thought 
quite probable this may be so, especially in vessels fitted with the friction brake shown in sketch 1 of 
Nig. 5. This brake is simple to operate and has on occasion been noticed to be well screwed down on 
vessels arriving in dry dock. 

Though it may not be possible to elicit from the reports of recent inquiries if the brakes were in 
operation when breakdowns in the steering arrangements took place, it certainly would be of interest if 
the author could state the percentage of casualty cases in which the different types of brakes were fitted, 
especially that shown on Sketch 1 of Fig. 5. 

The author is correct in stating that it is a common practice to buy the coil of the springs and 
make up the remainder of the fitting. This practice is confined not only to shipyards, but when a spring 
has become faulty in service owners also often only supply a new coil for fitting to the old caps and 
fittings. When this is the case the caps should be well examined, as it has sometimes been found that 
they too are not in a thoroughly efficient condition. 

In such a case that came under the writer’s survey, the completed spring was tested by the ship 
repairers on their chain testing machine before being fitted on the ship, but this is not always possible, as 
few ship repairers have chain testing machines on their p:emises. 

It is noted that the dimensions of the buffer springs are proposed to be standardised, and this 
appears necessary, as such vary considerably. 


10 


With regard to the auxiliary means of steering, in two passenger and cargo vessels recently completed, 
a warping winch was fitted inside the steering gear house with drums outside, and this used to operate 
the auxiliary gear. 


If it were compulsory to fit a deck house over the steering gear aft in all ships with a power winch 
inside, as in these vessels, it would lessen the difficulty of connecting the gear to the quadrant in addition 
to providing protection for the man operating the winch. 


Sometimes curious defects come to light in the course of survey work, and in one case when testing 
an auxiliary gear operated from one of two winches on the poop deck, having a connecting shaft between 
the two, it was found that the outside drums on each winch had considerably different diameters, one 
being 16 ins. and the other 22 ins. in diameter. It is obvious, of course, that the gear was not efficient 
and one drum had to be scrapped and a new one of proper diameter fitted. 


The author is to be congratulated on giving a very full and informative paper on this important 
| * 5 5 a) J 
subject. 


KE. H. Dean (Liverpool). 


| wish to thank the author for this very useful paper about a subject which has caused, and is 
causing those responsible for formulating rules for steering gear generally, much thought. 


My experience leads me to the conclusion that the rules as laid down by Lloyd’s Register appear 
quite adequate for the work required, provided the equipment is conscientiously and skilfully overhauled 
at frequent intervals. 


In conversation with the Assistant Marine Superintendent of a large shipping company running 
cargo ships from this port, he stated that he had sailed for many years with rod and chain steering gear 
and he had never had any trouble with the gear, and when asked if he could account for this, he stated 
simply, that at the conclusion of each round voyage the “steering gear gang” as they were called, appeared 
on board and opened up and overhauled all rods, chains and the gear generally. 


There is one thing that struck me about the unfortunate cases of loss which were investigated hy 
Lord Merrivale recently, in each case the last 8.0.8. picked up—if my mind serves me rightly—was to 
this effect—* vessel out of control, steering gear broken down.” Now this cryptic message did not give 
any indication of what part of the gear had given out, and as in most of the cases enquired into all lives 
were lost, those of us who endeavour to prevent such occurrences happening again will never know what 
part caused the trouble. 


If the Steering Gear Committee will formulate a rule that all rod and chain gear be opened up and 
overhauled once every three months, or as has been done in the cases cited, after every round voyage, they 
will I think, go a long way towards remedying the troubles which have occurred rather more often than is 
comfortable, recently. 


Turning to auxiliary means of steering gear; there is a method which would appear to ease the work 
of those who have the misfortune to be compelled to use this gear, when the auxiliary gear is tried out on 
new vessels on trial trips, special attention should be given to fix the length of wire required to take the 
necessary hard over to hard over on the winch drum, and to make arrangements for the loose end of the 
wires to be anchored to the winch drums. This would then necessitate only the attendance of men to 
operate the winch steam valve: if the length of the wires is not fixed and loose ends have to be 
manipulated round the drum ends one has to have very little imagination to visualise what difficulties 
would be encountered. 


Under the heading of fairleads and in the last paragraph, page 10—pins without brass liners which 
should be well lubricated as suggested, very often when opened up, are found to be in a dangerous 
condition; it is not uncommon in my experience to find these worn 50 per cent owing to lack of 
lubrication, and due to the fact that the pin becomes jammed and the fairlead ceases to revolve, causing 
undue pressure to be brought on to the pin. This would point to the fact that brass bushes should be 
fitted in all cases, as it appears that efficient lubrication is very seldom carried out in practice. 


11 


Turning to the question of spare gear with special reference to spare links for chains, it is known 
that there is on the market—and numbers have been supplied to vessels—a patent link made in halves 
horizontally and rabbited on alternate sides, as shown in sketch C. Now these links are made of 
malleable cast and two of these links were broken to destruction at approximately 25 per cent of the 
proof strain required for the steel welded links and it is imperative that should Surveyors come across 
this type of link among the spare steering gear equipment, they should point out to those in authority 
the danger which may be consequent if this type of spare link 1s used. 


Kk. Epwarps (Leith.). 


Mr. Buchanan’s paper will be of good service to those whose duty it is to make recommendations in 
connection with the fitting and upkeep of steering gears, and we are grateful to him. 


I will take this opportunity to mention one or two things which I think are worth keeping in mind 
when steering gears are being fitted. Concerning the control shafting from steering wheel to engine, a 
locking arrangement should always be fitted to prevent keys working out from the bevelled wheels, and 
when this shafting is carried on top of superstructures, ample arrangement of expansion joints. In the 
case of the jaws of connecting rods, shackles, and links it is concluded that the side of the jaw which takes 
the point end of bolt will be threaded so that the nut when fitted forms a jam nut. 


Concerning Fig. 10 of quarter blocks, when a housing of the type which takes the through bolt is 
likely to be submitted to a heavy side strain, it will be wise to fit a bracket at side, or the equivalent, to 
prevent possible racking causing the sheave to jam. Tillers are often kept as short as the Rules 
will allow; a slight increase in length, without decreasing the sizes of the gear, would ease up the whole 
arrangement, it would at the same time. of course, increase the amount of travel of the gear, and engine. 


L. H. Horne (Sunderland). 


Mr. Buchanan invites discussion for he deals with a subject of general interest and of particular 
importance to surveyors. Like all his other readers, | have found the whole of his paper most interesting 
but [ will confine my comments to one section, the old fashioned rod and chain gear. 


There seems to be a distinct tendency to-day to regard this system as out of date, and even 
dangerous. Now while, unquestionably, there are much better gears available for and usually fitted in 
large ships and high speed ones, there is a lot to be said in favour of the rod and chain gear for vessels 
engaged in the rough and tumble of coastal trade and similar services. The more elaborate steering 
gears withstand the pounding of heavy seas better, and if properly cared for suffer less from wear and 
tear, but I suggest they are more vulnerable to serious damage when the rudder receives a solid impact 
by striking a quay wall or in collision. 


The hydraulic, electro-hydraulic or electric gear must be kept in close alignment and a severe blow 
on the rudder is transmitted immediately to the steering gear or is absorbed by twisting or bending of 
the rudder or its head. With the rod and chain system there is generally considerable clearance round 
the pintles and the backlash there and elsewhere can often absorb a serious blow. Further, owing to its 
flexibility, the rod and chain gear will function even when considerable distortion has taken place in the 
rudder or stern frame. 

From the surveyor’s point of view it is easy to be prejudiced. When called on to survey a modern 
electro-hydraulic gear he deals with a piece of mechanism which is inherently interesting, opened out, 
clean and accessible and usually he has the cooperation of a thoroughly competent representative of the 
makers of the gear. 


Where he carries out a survey on an old rod and chain gear he finds its components strewn about 
decks covered with refuse, little is cleaned unless he has insisted on the cleaning, his job is essentially that 
of methodically examining a large number of items devoid of particular interest, it is raining down his 
neck and the superintendent assures him ‘that the whole of the cost of the repairs has to be borne by 
widows and orphans.’ 2 


12 


All the same it is submitted that for many services it remains as efficient as any other type of 
steering gear—if it is properly looked after. That, [I take it, is more or less the author's opinion, but 
there seems to be some risk to-day of government authorities being urged to take ‘panic’ action by 
people who have little knowledge of the subject and who imagine the latest and most expensive idea must 
always be the best. 


J. Housvron (Leith). 


The Staff Association is under a debt of gratitude to everyone who goes to the time and trouble of 
preparing a paper to be read before its members, and therefore I shall begin my remarks by thanking 
Mr. Buchanan for his paper on ** Steering Gear.” 

5 


It comes at a very appropriate time in view of the recent findings of the Steering Gear Committee, 
and of the emphasis which is now laid on the necessity of having the steering gear of every vessel in first 
class condition, This necessity was always present with us, but the regulations have now been tightened 
up, and it is hoped that there will be fewer casualties at sea in future owing to defects. It is appropriate 
also that the Association is to have a paper on “ Hatchways,” as there is a much closer relationship 
between “Steering Gears” and “ Hatchways” than some people imagine. A breakdown in the 
steering gear has been the primary cause of many vessels having their hatches stove in, often with fatal 
results. 


Mr. Buchanan gives us a description of most types of steering gears now on the market, with 
special reference to the ordinary rod and chain type. He points out that the Society’s Rules lay 
down the sizes of chains and rods, ete., for each size of rudder head, and that the Rules require that the 
chains should be tested. It has now been recommended that the material of the rods should also be 
tested. Mr. Buchanan gives an interesting resumé of what should be done in the way of testing and 
upkeep of these gears, but he makes no recommendations regarding the survey and testing of all new 
steering gears of whatever type they may be. Even before the setting up of the Steering Gear 
Committee | held the opinion that so vital an item of a vessel’s equipment as the steering engine should 
be surveyed during construction. I grant that the percentage of vulnerability of the engine itself is low 
as compared with other parts, especially in the rod and chain type, but it seems to me that too much is 
taken on trust when the prime mover in all gears is installed without any preliminary survey being 
required. 


A case in point came under my notice quite recently. A new vessel left on her maiden voyage after 
the usual trials at sea, which included steering gear trials such as circle turning, putting the rudder over 
from hardoyer to hardover, etc. Everything passed off satisfactorily, but the vessel had not. travelled 
300 miles before there was a complete breakdown of the main steering engine. Fortunately the hand 
gear was not affected and the vessel was brought safely into port. 


The gear in this instance is an electric one, with a motor driving a worm gear, which in turn drives 
a pinion geared to the toothed quadrant. The mechanism is totally enclosed, but it would appear that 
the shaft which takes the thrust was electrically welded, in accordance with the firm’s normal practice, 
and the cause of the breakdown was the failure of this welded shaft. I do not think that any classification 
society would have accepted this gear with a welded shaft, had it been known. I may add that other two 
similar gears, in vessels under construction, have been withdrawn, to have solid shafts fitted, in lieu of 
the welded ones. 


What about electric hydraulic gears with a working pressure of anything up to say 1,500 lbs. to 
the square inch? The cylinders and rams of these certainly should be examined under hydraulic test, 
but the Rules do not call for even that. 


It may be that, as a result of the Steering Gear Committee’s findings, the Committee of Lloyd's 
Register may embody some of their recommendations in the Rules. 


Mr. Buchanan makes mention of telemotor control, but says practically nothing about control rods, 
and the necessity of keeping these in good condition. Control rods and bevels call for a considerable 
amount of overhaul and repairs on occasions, and attention should also be given to them when being 
fitted in new vessels, as they still are. In a new vessel recently built in this district, these rods were led 


15 


underneath the shelter deck, and it was seen that no provision had been made for the lubrication of the 
bearings. This was attended to, but it might have been a case, in the not too distant future, of “out of 
sight out of mind,” until the moment when the controls jammed. 


In drawing these rambling, and perhaps somewhat lengthy remarks to a close, I would suggest that 
occasionally sufficient consideration is not given to the radius of the quadrant, in the rod and chain type 
of gear. Kverything may be taut and trim when the rudder is amidships. but, on account of the radius 
of the quadrant being too small, one side of the chain becomes slack and sags, and it may even, in 
extreme cases, fall off the quadrant altogether, when the rudder is put hard over. A little attention 
given to the design in the first instance can easily prevent this from happening. 


A. W. Jackson (Liverpool). 


The author is to be congratulated on presenting this very useful paper to the Staff Association, 
especially as it follows closely upon the Steering Gear Committee's Report made as a result of the recent 
losses at sea. 

At the top of page 21 the author states that “an alternative ar rangement of secondary means of 
steering is by means of blocks and tackle in conjunction with a separate tiller, keyed to the rudder stock, 
bul this method is very varely resorted to in this type of gear.” 

This statement is not strictly correct as two companies at present building oil tankers of about 
12,000 tons deadweight have tillers operated by single sets of rams and secondary means of steering as 
shown in Figs, (A) and (B) respectively. 

In Fig. (4) blocks and tackles are taken from a tiller keyed to the rudder head, the free ends led over 
sheaves through the poop deck to the drums of a warping winch. 


In Fig. (8) the free ends of the tackles from the tiller arm are led over sheaves through the poop 
deck. about eight turns are taken round a capstan and the whole system is made taut by means of a 
manilla tackle. This arrangement can be worked by the port or starboard capstan. 


The disadvantage of the secondary means of steering shown in Fig. (4) and also in Fig. 8 in the 
paper, is that the travel of the wire ropes on the winch drums is not the same for all positions of the tiller 
or quadrant, consequently if care is not taken it is quite easy to bend the warping winch spindle, bend 
the shackle pins or distort the structure anchoring the ends of the tackles. 


The arrangement in Fig. (s) suffers from the same defect as those previously mentioned in that the 
travel is different each side of the tiller arm, consequently if great care is not exercised the wire round 
the capstan drum will either unwind itself and one turn will overlap another when the direction of the 
turning rudder is reversed, or else the pulley blocks connecting the free ends from the tackles on the 
tiller arm will get too tight under certain conditions and the shackle pins will bend or the structure 
be strained, 


A great deal of care is necessary when operating secondary steering gears on trials, so as to ensure 
satisfactory results. One wonders what would happen in an emergency when it would be necessary to 
operate the secondary means of steering from such an exposed position as the poop deck. 


R. 8. Jonson (Copenhagen). 


It is admitted in the paper that the rod and chain type gear when properly maintained has proved 
efficient, and it is not seen therefore why all these additional rezulations should be imposed. For instance, 
one steering rod, about, has failed per year during the last ten years, and now they are to be tested. It 
may be considered that testing of materials is always desirable, but to argue that testing is necessary on 
the basis of such a record is hardly supportable. 

Similarly for spring buffers, the Steering Gear Committee analysed 334 cases of damage to gears 
which occurred over a period of ten years, of these 15 per cent relate to buffers. T’o assess any value to 
this one must know of what the damage consisted. Were they cases of fractured springs, or a rod, and 
was the chain rendered useless because of the extent of damage. Personally, I have experienced only a 
very few cases of broken springs, and rods broken through corrosion or a heavy weight falling on them, 


14 


and in no case has the gear been rendered useless in consequence. Weakness in this item as found by 
the author is not borne out in practice, and it is perhaps a question of basis and margin of strength 
inherent in the Rule requirements for the remainder of the gear. This does not say that any one item 
in the gear should be weaker than any other, but from the analysis on page 2 it is the chains and shackles 
that are the main trouble, and here it is that wear mostly occurs, and the remedy would appear to be one 
of maintenance. 


The Steering Gear Committee recommend that two buffers be fitted, but would not a double spring 
in the one buffer be a more compact alternative, one spring inside the other ? 
Db 


Warwick screws as fitted rarely give trouble; efficient means of adjustment of the chains is essential 
to enable the rudder to turn immediately in answer to the gear, which it will not do unless the spring in 
the buffer at once reacts to the force applied. This necessitates the spring having initial compression, 
which is only obtained when an efficient means of adjustment is available and is maintained. 


There should always be a degree of tautness present in the chains on both sides, which it may also 
be noted helps to prevent wear. 


Quadrants and tillers seldom give trouble. and the loose type quadrant is a very desirable fitting. 
Whilst from an experience point of view one cannot but defend the rod and chain type gear, it is thought 
that for many reasons a more extended use of modern methods and types of gear would well repay the 
initial cost of their fitting. 


R. B. SHEPHEARD (Hamburg). 


The author, in this timely paper devotes particular attention to the rod and chain steering gear and 
to its components. An arrangement of this gear which has been extensively fitted in German ships has 
a large circular quadrant, whose diameter is approximately equal to the width of the hatchways. The 
leads are carried alongside che coamings direct to the quadrant, quarter blocks being eliminated. The 
quadrant takes up considerable deck space, but the arrangement is simple, and the load on the gear is 
very considerably reduced. 


The leading of steering rods over the after well at the level of the superstructure decks is subject to 
serious objections, which are mentioned by the author, and it is considered that such an arrangement is 


most undesirable when deck cargoes are fitted. 


The satisfactory working of the rod and chain gear depends largely on the crew. The tension in the 
leads, for instance, may be suitably set at the time of survey, but this requires periodical adjustment, due 
to the stretch of the chains and the loading and working of the ship. Brakes and hand gears also need 
regular attention. At a recent survey the Mate and Chief Engineer of a small ship drew special attention 
to the well greased and good working condition of the hand screw gear. They had their reward when 
the ship was caught in a severe gale in October last causing a breakdown in the main steering gear. 


It is considered that steel wheels are much more satisfactory than teakwood for hand gears. The 
latter are often badly neglected, and spokes have broken off in some cases when the gear was put into 
action in emergency. 


An interesting adoption of the hand hydraulic steering gear has been fitted recently to several small 
German built ships of fairly full form having twin screws. Two streamlined spade rudders are fitted in 
the propeller stream. Double tie rods connect the tillers to the after end of a central tiller, at the fore 
end of which the rams of the hydraulic gear are fitted. The rudder heads are about 43 ins. diameter, 
and the gear is easily controlled by one man from the wheel house; giving excellent steering. The 
hydraulic gear can be used as a brake, independent shut off cocks being fitted to each cylinder. A hand 
screw gear is arranged as alternative means of steering. 


New types of power steering gear of simple, robust and economical design, to be fitted at the rudder 
head, are being continually developed. The power necessary is also lower, due to the reduced twisting 
moment with modern streamlined and semi-balanced rudders. It seems. therefore, probable that the less 
efficient rod and chain gear will in the course of time be eliminated, with few regrets, at least on the part 
of outport Surveyors. 


y 


15 


S. TowNsHEND (Gothenburg). 


Although the Staff Association has now been in existence 16 years, this is the first paper that has been 
read on this very important subject. It may be that there is a reluctance to deal with the matter owing 
to the fact that steering gears are generally considered to be rather a specialist’s job, and therefore our 
thanks are especially due to Mr. Buchanan for his paper, and for the very complete and comprehensive 
data he has got together for us. 


The author points out that although the initial damage may be small, the subsequent damage due 
to a defect in the steering gear may be very serious. In addition to causing collision or grounding 
damage, a breakdown in the gear can also involve the complete loss of the ship. In very severe sea 
conditions safety depends entirely on the ability of the master to keep the ship head on to the waves with 
just sufficient speed to prevent veering. A temporary loss of steering control will quickly allow the ship 
to lie broadside to the waves, and the damage done then may immediately be of such a nature that the 
vessel never recovers, even if control of the steering is soon re-established. 


In Sweden the gear most used is of the electric-hydraulic type and there are no doubts about its 
efficiency and reliability. I agree with the author that when two pumps are fitted and the auxiliary 
means of steering is dispensed with, two entirely separate leads of cables should be provided. One set 
might be taken along below the weather deck and the other could be led along the tunnel and up the 
tunnel escape or tunnel ventilators. Fire in the ‘tween decks can easily put the steering gear out of 
action by destroying the cable leads if they are led aft below the deck. 


As regards auxiliary means of steering it has been noted in vessels of about 3,000 tons gross and 
above, that the hand gear is very hard to work, and I doubt if it could be effectively manipulated if 
required to be used in very heavy weather. A block and tackle arrangement would appear to be better 
in such cases. 


The author states on page 15, third paragraph, that when chains require to be repaired the affected 
links are replaced by new links cut from a tested chain. I presume the idea here is to avoid testing the 
repaired chain and, if such is the case, are the new links connected to the old chain by tested shackles ? 
Difficulties may arise because the available shackles require an enlarged end link to ensure proper 
‘*bedding,” and in such cases the testing of the repaired chain appears unavoidable. 


In the formula quoted by the author for the force on the rudder, viz., 2 AV? lbs., given on page 3 
under ** Steering Chains,” he defines V as the speed in knots. It is usual to increase V by an amount 
representing propeller race, and it appears to me this would somewhat affect the values of factors of 
safety quoted. 


On page 4, second paragraph, the statement is made that the diameter of the rudder stocks and the 
size of chain are based on the maximum speed of the vessel. I doubt if this is really the case in average 
practice. The speed to be used in calculating rudder heads is not precisely defined, and objections are 
not raised if the service speed is adopted instead of the maximum speed or speed on trial. 


C. A. TOWNSHEND (Belfast). 


I thank the author for a very comprehensive paper, which has arrived opportunely. 


It is interesting that the Steering Gear Committee has not condemned the rod and chain method, 
but in the ordinary cargo boat of moderate dimensions the practical difficulties of providing an 
alternative are many. 


In my experience the rod and chain method is found satisfactory enough, but requires constant 
supervision on account of the reduction of wearing parts, such as at the steering rod ends where the 
holes become elongated, the rods where they pass over their supports, and the chains where they pass 
round the quarter blocks. The rod supports commonly have hard wood bearings, which are better than 
steel rollers, which revolve when new but rust wp as soon as the ship is at sea. The connection of the 
chains to the quadrant, as the author remarks, is at times a source of trouble and the hand gear, if fitted, 
should be frequently tested and the threads of the screw spindle kept clean and greased. 


The wheel should be of all metal or brass bound teak, as I have known them go to pieces when of 
wood only when used in an emergency, as has also the whole gear on account of the pedestal brackets 
being too lightly constructed. It has to be borne in mind that auxiliary methods of steering have 
oftentimes to be put into operation in darkness and the worst of weather conditions. 


In the course of my surveying duties I have met with a few failures which might prove of interest : 


1. Oil tanker. Steering gear in deckhouse with projecting arms, supported at ends by pedestal 
bearings as explained on page 2 of the paper. One arm sheared between house side and pedestal 
during gale, presumed through rusting up of bearing and causing resistance to turning. Vessel 
nearly lost. 


2. Timber carrier. Rod connection broken during a gale in mid Atlantic. Holes in jaws and 
eyes elongated, and one pulled through. Deck timber had to be part jettisoned to effect a 
temporary repair. 

3. Three island cargo vessels :— 


(a) Single drum at centre line of ship and quarter blocks abreast same pulled away 
from deck. 


(6) Similar drum and chain connection broke. Vessel grounded in consequence. 


(c) Chain connection to quadrant broken and hand steering gear collapsed when brought 
into use. Return had to be made to steam gear and temporary repair effected while 
ships standing by in response to SOS calls. 


(d) Chains passed from upper to poop deck and blocks pulled away from poop front 
bulkhead. 


The various types of steam, electric and hydraulic gears situated above the rudder are all more or 
less equally efficient, and the only comment I can make is that they should be so designed that when it is 
required to lift the rudder the adjustments necessary should be small in order that they may be made 
rapidly. 

Again I thank the author for a very useful paper. 


A. Warr (Neweastle). 


The author has given the Staff Association an excellent paper on a vital branch of ship building and 
marine engineering. Even in its present form the paper, if reprinted in the form of a pamphlet, would 
be of immense value to ship draughtsmen and superintendents, and would saye surveyors much time in 
discussing defects in design with superintendents and/or shipyard managers. 


On page 11, paragraph 1, under Rudder Brakes, the author considers that ‘it is possible that the 
brake had been kept partly screwed down and the friction segments had worn away.” It would be well 
if his further remark regarding the proper use of the brake be emphasised. It appears that the brake is 
mis-used at times through ignorance on the part of the ship’s officers and crew, and without the 
knowledge of the owners’ superintendent. One case in point is that of a vessel which was overhauled 
afloat before a winter voyage last year. The rod and chain gear and the steam steering engine in the 
engine casing were thoroughly overhauled, and the quarter blocks, which are of the type shown in 
Fig. 10, left side, were all examined. 


A few days after the vessel left the Tyne steering gear trouble was reported, and later we were 
informed that one of the midship quarter blocks had been torn and broken away from the deck, due to 
the brake having been screwed down to “ relieve” the rudder of shock loads. The superintendent has 
now is-ued special instructions to his deck officers with a view to obviating similar occurrences, 


In connection with the upkeep of “ hydraulic” two-ram steering gears, it might be mentioned that 
several casualties have occurred due to the fracturing at the necks of the pipes which carry the oil 
between the ram cylinders and the pumps. These pipes and ram cylinders work at pressures in the 
vicinity of 900 Ibs. per square inch and the cylinder relief valves are set at 1,000 lbs. per square inch. 


17 


In one case, When the pipes fractured at the neck, the cylinders were emptied of oil and the rams 
were slammed from side to side by the heavy seas striking the rudder. In such cases, i.e., two-ram gears, 
would it not be advisable to have an efficient brake fitted 2? A simple and effective brake could be fitted 
to the crosshead of a two-ram gear. 

Special attention should be paid at heavy weather damage surveys and at special surveys to these 
high pressure oil pipes, which are subjected to considerable racking and shock stresses during heavy 
weather. Sometimes it will be found that the pipes leak at the flange necks and, before the surveyors 
are informed of the trouble, the repairers—no doubt at the instructions of the owners’ representative—will 
whip the pipes to the shop and have the necks electric welded. Sometimes they come back with a large 
fillet at the flange and an undercut round the pipe necks. This method of repair should be discouraged. 

The practice of one of the best known makers of steering gear in this district is to serew the pipe end 
with a vanishing thread into its flange, the pipe end is then expanded, and the joint end is veed and 
electric welded and the joint face is machined. 


REPLY BY THE AUTHOR. 


The paper has produced a very interesting discussion, and I am sure that this will be of service to 
every surveyor, particularly as regards the efficiency of the rod and chain type of gear which, naturally, 
has come in for the most criticism. 

The general opinion appears to be that this gear, if properly looked after and surveyed at reasonably 
close intervals of time, is efficient, although there seems to be some divergence of opinion on the subject 
of auxiliary gears. 

Mr. Thompson has drawn attention to the fact that the majority of the defects which are reported 
relate to the chains and the pins in the guide blocks. It is possible that the limits of wear now proposed 
for the chains may to some extent reduce the number of broken chains and, if brass bushes are fitted to 
the pins of the guide blocks, and they are kept well greased and periodically examined, there is no reason 
why these should give any trouble. 

He also raises doubts as to the strength of the hand steering gear of the left and right-handed screw 
type, and I agree with him, but I think its principal drawback and source of trouble is the complete lack 
of shock absorbing facilities. 

Mr. Potts instances a case in which cargo was damaged due to carrying the steam pipes for the 
steering gear along the tunnel and perhaps, judging by this example, the word “ideal” was not the 
correct one to use. Nevertheless | think this must be an exceptional case and that the disadvantages of 
the alternative arrangement greatly outweigh this problematical advantage. I have to thank Mr. Potts 
for giving us an indication of the required thickness of quadrant plates. As he says, this will give an 
easy method of achieving approximate standardisation in this matter. 

Mr. Young puts forward some interesting suggestions regarding the cushioning properties of the 
electro hydraulic gear. For ordinary purposes of steering in rough weather, and to overcome the movement 
of the rudder which results, the manufacturers appear to think that the relief valves which they fit fulfil 
their purpose, aud as Mr. Young mentions, the gear has given proof of its reliability. 

The twisting of rudder stocks is a comparatively rare occurrence and it cannot be said that more 
oceur with one type of steering gear than with another, so that, as far as I know, no case has been made 
out for an increase of stock when an electro-hydraulic gear is fitted. The majority of these gears are 
installed in vessels of medium to high speed and the stocks have already been increased on account of this 
higher speed. 

The fitting of the double lead of telemotor pipes to the gear, in different parts of the vessel, would 
remoye any doubt as to the efficiency of this portion of the installation, although it does not appear quite 
so vital as separating the cable leads. 

In the event of a breakdown in the telemotor control system, the rotary oil pumps may still be operated 
from a position adjacent to the gear, -but, if the cables are destroyed this is impossible, and the auxiliary 
gear of a four ram system would also be put out of action. Mr. Beveridge advocates the abolition of the 


1s 


rod and chain type of gear. While I agree with him that, for vessels with timber deck cargoes, a rod and 
chain gear is not at all suitable, I cannot agree that, because some vessels with this gear have been lost, 
the type should beabolished altogether. We know thatit is more subject to damage than any other gear, but it 
is towards improving the arrangement to which we should direct our attention rather than banning the 
gear altogether. 

Mr. Beveridge draws attention to the advisability of fitting brass bushes and grease cups to the quarter 
blocks and this is a point which should be emphasised. It is generally agreed that chains, after repair, 
should be tested but, unfortunately, the appliances abroad are not so common as could be wished. The 
carrying of a spare length of chain may result in the testing of repaired chains being the universal 
practice. 

Mr. Anderson disagrees with the statement that the length of chain between the quadrant and the 
buffer spring takes the load without any relief. While, theoretically, with a dead load applied at the 
quadrant, the same relief is given to all the chain by the spring, | think that with a live load 
instantaneously applied the greater amount of the stress will come on the length of chain mentioned 
before the effect of the spring can be felt, and this is, to my mind, borne out by the fact that the 
breakages to chains and the damage to sheaves takes place in this vicinity more than in any other. 


The only way to prove or disprove this contention would be to measure the strain in practice, which, 
as far as I know, has not been done. With regard to the rod connections and connecting links shown in 
Fig. 3, one side of the jaws is screwed to take the bolt, so that the nut acts as a locking nut and the jaws 
cannot be pulled in to the same extent as would be the case withont this arrangement. 


Mr. Blocksidge expresses the opinion that too much importance is given to statistics. I know it is 
said that figures of this kind can prove anything, but 1 was attempting to point out that the wholesale 
condemnation of the rod and chain gear was, in my opinion, unwarranted, and the figures used are those 
obtained from the Steering Gear Committee report. 


He also thinks that the hand gear is more efficient than the block and tackle arrangement. of 
auxiliary gear. Certainly the block and tackle arrangement is more difficult to rig up, but from a 
perusal of the damages sustained by vessels when the auxiliary gear has been resorted to, | am of opinion 
that the hand gear is more liable to be put out of action due to a heavy sea than is the other 
arrangement. In fact, on a number of occasions in which the hand gear has been damaged, the vessel 
has been brought into port by means of a jury rigged block and tackle. 


In reply to Mr. Blocksidge’s question regarding the method of holding the rudder steady during the 
change over from main to auxiliary gear, any of the friction or oil brakes shown in Figs. 5 and 6 will 
keep the rudder reasonably steady when required, and although there have been cases of these not 
functioning properly, it has been because the brakes were not maintained in good condition. 


T agree with Mr. Stocks that the rods and chains should be slightly weaker than the rudder stock, 
although I cannot quite see his objection to the factor of safety. It is purely a ratio between the known 
strength of the chains and a working load ealculated on an empirical formula which is generally accepted, 
although this ratio is given for a static load and may be reduced considerably due to a blow by a wave, 
the force of which cannot be calculated. 


Mr. Stocks’ suggestion of the two compression devices operating at different loads is interesting, bub 
could this not be done with a spring of sufficient size and number of coils to close solid at about the 
proof load of the chain ? For lesser loads there would be less compression. With the two devices, one 
spring could be very much smaller than the other, and giving more movement than the single spring 
would give more relief. Mr. Johnson suggests something similar, with one spring fitted inside the 
other. 


I have never heard of any trouble to quadrants due to the fitting of runners, but the adjustment required 
due to the lowering of the rudder would have to be attended to. As most of the quadrants with steam 
gears at the aft end of the vessel are also fitted with runners, the same will apply to these. 


Mr. Bryden draws attention to the fact that the key in Fig. 1 is driven in from the bottom. This 
is an exact copy of a working drawing, but I cannot vouch for the fact that the quadrant was fitted in this 
manner, and I think he is probably correct in assuming that it was not. He also asks for the percentage 
of losses due to damage to steering gears. 1 am afraid this figure is impossible to obtain. 


1g 


On an average about 12 casualties to British vessels over LOO tons gross are reported each year under 
the heading abandoned, foundered or missing. This figure does not include those sunk due to collision, 
grounding, etc., which may also be due to steering gear failure. Board of Trade enquiries which give the 
probable cause of loss are held on only a proportion of these, and therefore any percentage based on the 
findings of these enquiries would give a purely fictitious result. 


Mr. Shilston has told us of an experience on a vessel without a rudder brake and contirms the 
importance of this fitting being adequate to carry out the work it is intended to do, He also raises the 
question of protecting the after winch. The Steering Gear Committee considered that there appeared to 
be no generally practicable method of providing this protection. While no hard and fast rule can be laid 
down, it should be emphasised that, if it can be arranged, the after winch should be given some form of 
protection, and in doing this, the efficiency of the block and tackle auxiliary gear would be greatly enhanced. 


Mr. Roberts states that long links at the end of a chain are desirable, and the statement made in the 
paper was that they were only necessary at certain times. If the chain is originally tightened to the 
extent that is advocated, the stretching that will take place in one voyage, even with a new length of chain, 
while it may be considerable, could be ‘taken up by the stretching screws. If the ship’s staff examine the 
tension of the chain at short intervals of time and remove end links as necessary when the vessel is in port, 
I think the tension could be maintained without requiring to shorten the chain at sea. 


The figure of ,!, in. given by Mr. Roberts appears to me to be more than would be the normal wea 
on each link in the ler ith of time between examinations. Although the shackle pin will pass eae a 
short link, if long links are fitted at the end of a chain, the shortening becomes a much easier matter as 
the shackle pin will pass through a long link with the adjacent link in position, but in this case it would 
require to have more than one long link at the end to be of much use. 

Mr. Rannie asks if there is any reason, apart from a mechanical one, of fitting the purchase direct to 
the quadrant. There is none except that a 4% in. wire costs more than a 24 in. wire, and if it can be done 
without, so much the better. I agree with him that a single wire would be probably easier to attach to 
an exposed quadrant than a purchase, but my opinion is that both would be nearly impossible without first 
bringing the quadrant to rest by means of the brake. 

Mr. Ritchie has drawn attention to the additional risk of damage due to deck cargo being carried 
with steering gear of a rod and chain type. I have mentioned this previously in these notes, but it is a 
danger which cannot be emphasised too much. His remarks regarding hasty and ill considered legislation 
are very apt at this time. 

[am sorry I cannot obtain the particulars of the brakes which Mr. Craig asks for. No details were 
given of the rudder brakes fitted to the vessels lost in the majority of the enquiries which were held, 
although this information is given in one or two cases, and in at least one of these the brake was unsound 
due to general neglect, | don’t think the fault lies in the type of brake but in the misuse to which the 
brake is put. 

It is interesting to note that buffer springs are sometimes tested after repair. As Mr, Craig remarks 
this is not always possible, but if the appliances are available, it is advisable. I have mentioned before 
the question of protecting the after winch, and here is definite evidence that it can be done, although I 
doubt whether it is practicable to make it compulsory. 


The Steering Gear Committee have recommended that the rod and chain gear be opened up and 
examined every three months as indicated by Mr. Dean, but unfortunately, due to the great variation in 
the length of time in port which vessels of this type have, it is not always possible to attain this perfection. 
Nevertheless, Mr. Dean and many other writers have confirmed the statement that it is only by 
periodic and vigorous examination that this type of gear can he kept efficient. I have seen samples of the 
patent link mentioned, both before and after testing, and I am surprised they stood even 25 per cent of 
the proof load, and I would draw attention to the warning expressed by Mr. Dean. 


Mr. Edwards and Mr. Houston have mentioned faults which may be experienced in control shafting. 
This portion of the gear probably does not receive the care which is given to the engine and other parts, 
and, in some cases, the rods have to be removed in the vicinity of the bridge deck hatch when cargo is 
being loaded and discharged. They generally require to be replaced in a hurry before sailing, and it 
seems a design which might lead to trouble. ‘As explained previously, one jaw of the shackles is screwed 
and the nut forms a lock nut. 


20 


The suggestion regarding the increase of length of the tillers would certainly increase the strength 
of the gear and is to be advocated, but unfortunately the Rules, instead of ‘being considered a minimum, 
are looked on as exact figures not to be exceeded. 


Mr. Horne’s suggestion that the newer gears are more vulnerable to a serious blow is in line with 
Mr. Young’s remarks concerning the cushioning properties of the electro hydraulic gears, and I am 
inclined to agree with him, if only from the fact that the rods and chains are practically bound to give 
way before any material damage can be done to the engine. The remarks concerning panic legislation 
are so entirely in agreement with those of our President that no more need be said. 


I have already mentioned Mr. Houston’s remarks in regard to control rods, and he also gives us an 
example of faulty workmanship in the engine itself. This is probably a rare occurrence, as the engine 
appears to be comparatively free from defects, but it shows that faults of this kind can take place, even 
with the test which is placed on the steering gear during a trial trip. 

Mr. Jackson does not agree with my statement that the block and tackle auxiliary is not generally 
used with an electro hydraulic gear and gives us two interesting examples. I was aware that this method 
had been used in a number of tankers lately, but this is a very small percentage of the vessels which have 
been fitted with this type of main steering and a hand operated auxiliary gear. 


The first objection which presents itself is the very involved system of blocks and tackles which is 
necessary. To have to rig this up in dirty weather at night seems to be well-nigh impracticable. It is 
well that the main gear has a very high degree of efficiency and that the auxiliary gear is seldom required. 
The second objection Mr. Jackson has himself drawn attention to. 


In a case of this type the only safe method appears to be to keep the auxiliary gear rigged up and 
adjacent to the quadrant, so that all that requires to be done is to fasten the blocks to the tiller. This 
objection of an involved lead is not so evident in the rod and chain arrangement, due to the fact that it 
is alt on one level and there is more room on the poop deck, but nevertheless it is always present. 


Mr. Johnson objects to my statement that the buffer springs are too weak and he states that he has 
experienced very few cases of broken springs. In the paper I remarked that it is unusual to find a spring 
broken in the coil, but my contention is that the buffer springs close up solid and, as so aptly put in the 
discussion, ‘ bye-pass the shock.” In this way the full shock comes on the chains and rods, which, as 
Mr. Johnson says, are the main trouble. If the springs were increased in size it seems probable that the 
result might be a lessening of the damage to the chains, although 1 agree that maintainance is the best 
deterrent to failure. ; 


I had the pleasure, a short time ago, of seeing a rod and chain gear of the type described by 
Mr. Shepheard, and it was a distinct improvement on the usual gear of this kind. In this case the 
quadrant was fitted inside the poop and from the steering engine, which had extended barrels, a straight 
lead of chain passing through the poop front, was possible. I am indebted to Mr. Shepheard for his 
description of the hydraulic arrangement fitted to the German vessels. It is somewhat similar to that 
described in the paper, with the exception that it has been modified for twin rudders. 


Mr. 8. Townshend advocates the use of the block and tackle gear in preference to the hand gear in 
vessels of over medium size, and I think he will find that, in future, this will become compulsory, the 
hand gear of the left and right handed screw not being allowed in these vessels. When new links are 
fitted in an existing length of chain, links require to be forged joining the old and new portions. When 
the appliances are not available for testing the completed chain, the workmanship of the blacksmith has 
to be taken for granted, except for a visual examination. The speed taken for the factors of safety given 
included a percentage for propeller race, as pointed oui by Mr. Townshend, but they only apply to the 
10 knot ship, as those for 12 knots are lower than those given. Attention has also been drawn to the 
question of the speed used in assessing the rudder scantlings. I suggest with some diffidence that even 
the service designed speed is in excess of that usually attained in practice. 

Mr. C. Townshend mentions the advantage of the steel or brass bound teak wheel for the hand gear, 
a point also mentioned by Mr. Shepheard. These wheels have to stand a big strain, and the stronger 
they are the better. A very interesting list of damages is also given, and in one case the jettisoning of 
part of a timber deck cargo is mentioned. While it is hardly to be expected that these accidents will be 
entirely eliminated, they may be reduced in number with care and attention to the gear. 


a 


Mr. Watt raises the question of brakes being fitted to the two ram electro hydraulic gear, I agree 
that under the circumstances mentioned, a brake would have been invaluable. With the type of hand 
gear usually fitted with an electro-hydraulic gear, i.e., incorporating a friction clutch, it does not appear 
absolutely essential but without this arrangement, i.e., with a block and tackle gear, it is practically 
indespensable. A note of warning is also sounded regarding the welding of pipe flanges on the electro 
hydraulic gears. 

I have been informed that the fault mentioned at the foot of page 22, that is, the compass being 
affected by the electric motor on the bridge did not take place in a gear of the type described, but on a 
similar type of gear made by another firm. As no confirmation of this effect has been mentioned in the 
discussion, we may take it that there was some exceptional circumstance in the case mentioned. 


It has been pointed out that one or two slight errors appear in the paper with regard to the 
numbering of sketches and I have to thank those w ho drew attention to the matter. Finally y would like 
to thank all those who very kindly took part in the discussion, and enhanced the value of the paper to 
such a great extent. 


= Warring WiNcH 


HoLe iN DECK 
oie es PoRTABLE PLATE 


RECESS in BKD \ 


THLLER ‘ eA TAKING SHEAYES 


Wick DRUM 
(OVER ) 


W. Jackson’s CONTRIBUTION. 


ILLUSTRATING A. 


Poor Ox. 
J-TRAYEL OF MANILLA TACKLE Blocks +1 


——— 25 
| ROLLER 
| LEADS & TURNS OF 
WIRE ON CAPSTAN 
i aes 
<1. rar 
MANILLA TACKLE 


FOR TAKING UP SLACK 


CAPSTAN. 


Upper Deck 


SHEAVE 
DECK. 


LEO THROUGH 
ON Poop 


ILLUSTRATING A. W. Jackson’s CONTRIBUTION. 


arene 
Wy NSS 


SECTION 


HOLE FOR SPIGoT 


TESTED Link Top HALF 


BROKE HERE 


HOLE FOR SPIGOT 


BoTTom HALF 


PLAN. 


Fic. C. ILLUSTRATING E. H. DkAN’s CONTRIBUTION. 


HATCHWAYS. 


By J. G. BUCHANAN. 


Reap 38RD DrcEmMBeEeR, 1936. 


It appears, from a perusal of the Transactions, that a paper with the above heading has never yet 
been read before this nor any of the other British Technical Societies, presumably on the score that such 
a paper could not contain sufficient technical information nor register much divergence of opinion from 
the usual accepted method of hatchway construction, nor would there emanate anything from the 
discussion which would be of any practical benefit to the shipping fraternity at large.” It is, therefore, 
with some diffidence that I present this paper, lacking, as it does, in abstruse calculations and theoretical 
observations. Nevertheless, I am of the opinion that the subject is of paramount importance and 
deserves more attention than has hitherto been given to it. 


Hatchways are, and always have been, the most vulnerable part of the vessel ; notwithstanding this 
truism, until recently very little progress has been made towards the long overdue improvement. in 
closing these extremely large openings in the decks of ships. At least, nothing like the same progress 
Ww hich has been made in the design of rudders, steering gears, lifeboats, cruiser sterns, Meier form bows, 
the general elimination of redundant strength members, welding instead of riveting as the mode of 
fastening, or in the vessel as a whole, from wood to iron thence to steel and now, in parts, to high tensile 
steel. Through it all, the hatchway remains reminiscent of the old wood ship, being closed by bits and 
pieces of w ood and made w eathertight by tarpaulins. 


One marvels at the meticulous care which is sometimes exercised in seeing that all the steel items on 
board a ship are maintained in order; should a sprung beam rivet be replaced by the crew, in their 
wisdom, with a good fitting bolt, well grummetted and screwed up tight, the owner, as soon as an 
observant surveyor has seen this * tempore ary repair,” knows no peace until he has engaged a squad of 
riveters to make this connection a proper and permanent one. At the same time, however, it is possible 
that the twenty or more single plank covers in the width of the hatchway could each have shrunk one 
quarter of an inch making a total gap of, at least, five inches through which water is only prevented 
from entering the hold by two thicknesses of canvas. These instances may appear exaggerated or 
imaginative but the author is aware of their reality. 


When a vessel is long overdue, a not unusual hazard is that she must have encountered heavy 
weather and had her hatches “ stove-in.” Seldom, if ever, is the possibility considered that her tail shaft 
has broken or her rudder got adrift or the steering chains failed, such mishaps causing her to fall into a 
trough of the sea and capsize by the shifting of cargo. No, the general opinion is * hatches stove in.’ 
Why ! because as before stated, the hatches are known to be the most vulnerable part of the ship. 


It may appear strange but it is nevertheless true that until 1932 there were no statutory detailed 
regulations for the construction and closing of hatchways; classed vessels, of course, were obliged to 
conform to their own Society’s requirements, but an owner of a vessel which was not classed with any of 
the registration societies could have his own ideas, within limits, of how best to close these deck openings, 
and if the Board of Trade did not consider the scantlings or arrangements quite satisfactory they could 
not, with ease, compel the owner to conform to their way of thinking. 


After all, the interpretation had to be made of the paragraph in the old freeboard regulations which 
stated “The freeboards required by the rules and tables are to be assigned on the condition that the 
weather deck hatchways are properly framed with swbsfantial coamings, and strong hatch covers, the latter 
being efficiently supported by shifting beams and fore-and-afters swifable to the dimension of the 
hatchw ay.” and therein opinions could ‘differ with regard to the five words, properly, substantial, strong, 
efficiently and suitable. 


During the investigations which the Load Line Committee made whilst framing the new freeboard 
rules it was found that the cause of 13 per cent of the vessels lost at sea was failure of hatches. It is 
the author’s opinion that this percentage of vessels lost due to this cause could be substantially reduced, 
and that the present arrangement of closing the hatchway openings as prescribed in the statutory 
regulations is satisfactory only provided that the greatest care is taken in the maintenance of all the 
component parts of the hatchway. It must not be inferred, however, that all ship owners neglect this 
part of the vessel but even in the best regulated and managed companies instances have been noted when 
the condition of the covers left much to be desired. With all due respect to the individuals, many of the 
British superintendents are engineers and leave the maintenance of the hatchways to the master and 
mate ; not a bad idea, either, as these are the men who are to sail in the ship and one would naturally 
conclude that they, at least, would make sure that everything of a seaworthy nature was always in 
order. In the larger ships a carpenter is carried and he is generally supplied with sufficient wood to 
repair or renew covers as they are required on the voyage. 


It surprised the author greatly on one occasion to find that when a vessel, owned by a firm of some 
repute, was submitted for her first No. 1 Survey—she was about five years old and had been abroad for 
two years, was about 400 ft. long and had five main hatchways—no less than 93 (or 44 per cent) of the 
weather deck hatch covers had to be renewed ; these were double plank covers and cost approximately 
30]- each. The mate and carpenter were both dismissed their ship and rightly too, for they not only 
endangered their own lives but also the lives of all of those on board. 


In 1880 Mr. Benjamin Martell, the then Chief Surveyor to Lloyd’s Register of Shipping read a 
Paper to the Institution of Naval Architects on ‘ Causes of Unseaworthiness in Merchant Ships” ; in his 
Paper he dwelt on a number of items contributing to unseaworthiness and one was “the inefficient 
protection of the openings in decks.” That was 56 years ago and the size of hatchways then was 
nothing like what is fitted to-day: then Lloyd’s Register required a special plan to be submitted when 
the length of the hatchway exceeded 20 ft. ; to-day the freeboard tables contemplate hatchways 30 ft. in 
breadth and lengths of 35 to 40 ft. are not uncommon. During the past half century the various 
classification societies have formulated rules and tables, extended the tables as the size of the hatchways 
increased and augmented the rules by the inclusion of and a more detailed description of the components 
as their importance became apparent. However, the method of covering the openings to-day is the 
same as it was 50 years ago. 


It is not contended that the strength or arrangement of the system is deficient or unsatisfactory 
when the vessel is new but it is thought by the writer that, owing to the increasing size of hatchways 
and the multiplicity of parts involved, the perfect control which should be over this important part of 
the structure is difficult to maintain. 


The Paper sets forth a number of weaknesses which can be expected in this system and describes a 
number of innovations which are taking place in hatchway construction. It is only logical to assume 
that the strength and tightness of these large areas should always be equivalent to the surrounding deck 
and a steel covering would seem to be the ideal arrangement. As the wood and tarpaulin method is 
never considered to be absolutely watertight, but only weathertight, it remains to be seen whether a steel 
covering can retain this feature. 


The fitting of steel watertight hatch covers is not considered to be absolutely care-free ; the 
jointings, whether of greasy hemp or rubber will require to be frequently examined and renewed. 
While damage to cargo might not altogether be eliminated it is thought that the safety of the ship would 
be enhanced by the fitting of steel covers. 


QUESTIONS IN PARLIAMENT. 
Asan indication of the interest which the subject of hatchway construction is creating, the following 
are some of the questions which have been asked in Parliament recently :— 
On March 25th, 1935, Sir B. Peto asked the Parliamentary Secretary to the Board of Trade whether 
his attention had been drawn to the recent experience of a steamer in exceptionally heavy weather, when 
the safety of the ship was attributed entirely to the fact that the hatches were covered with steel casings, 


and whether, in view of other cases of loss he would institute an inquiry into the loss of these ships 
and consider the question of making the steel casings of large hatchways compulsory in all ships trading 
in the North Atlantic and other waters where heavy seas were normally encountered. 

Dr. Burgin: —* The answer to the first part of the question is in the affirmative. he extent to 
which recent casualities have been due to the failure of hatches will no doubt be brought out in the report 
of the formal inquiries, and these reports and any other relevant information will certainly be fully 
considered.” 

April Isl, 1936. Mr. Adams asked the Parliamentary Secretary to the Board of Trade whether the 
revised regulations for the mercantile marine would include a report as to the safest types of hatch 
coverings to be used. 

Dr. Burgin :—* The Load Line Rules, 1982, contain the general requirements with which hatchway 
covers must comply and the instructions to the officers concerned require special attention to be given to 
the condition of these fittings at each annual load line survey. — Specific types of covers are not required,’ 

July 9th, 1936. Mr. D. Adams asked the President of the Board of Trade whether for the purpose 
f ensuring greater safety at sea, he proposed to make angle cleats uniform in all existing vessels. 

Capt. Crookshank, replying for the President of the Board of Trade, said the question was under 
consideration. 

Mr. Adams also asked the President whether, in view of recent experience, his department was 
satisfied with existing types of hatch coverings, and whether he would consider the desirability of a 
uniform type of steel hatch covering for future tonnage. 

Capt. Crookshank :—* [am advised that the existing type of hatch coverings, when in good condition 
is satisfactory. While the Board of Trade examine the designs of steel hatch covers in order to decide 
Whether covers of a particular design may be used on British ships, they are not prepared to insist that 
all hatch covers shall be of steel or that any particular type shall be used.” 


History OF THE DeVELOPMENT OF HATCHWAYs. 


Prior to the Freeboard Tables of 1885 there were no statutory rules for the construction of hatch- 
ways, the scantlings and arrangements, presumably, being left to the discretion of the master and 
shipbuilder. For a historical record of the development and progress in construction of hatchways one 
cannot do better than refer to the past Rules of Lloyd’s Register of Shipping. 

In 1855, Lloyd’s Register published the first rules for the building of iron vessels, but it was not 
until the 1865 Rules that any direct reference was made to hatchway construction, and that was meagre 
enough, simply stating that * All hatchways are to be properly framed to receive half beams where 
required.” 

This rule continued until 1879, when something more definite as a rule was inclnded in that year’s 
publication, and, briefly stated, was :— 


“Upper deck hatchways between 12 and 16 ft. in length to have strong shifting beams titted 
With proper means for firmly securing same. Between 16 and 20 ft., a deep web plate to be fitted 
between double angle irons, at the middle of the length, extending the depth of the coming and 
carlings. When the length exceeds 20 ft. a deck plan is to be submitted for the approval of the 
Committee, showing the necessary additional strength proposed to be applied, by increasing the 
number of web plates. All hatchway comings on. weather decks to be of iron. In vessels having 
long hatchways for the purpose of “self-trimming,” wing boards are to be fitted to the approval of 
the Committee, to prevent the shifting of cargo. All hatches of steamers to be solid and not to be 
less than 24 ins. in thickness. 


A sketch was also given, showing the typical arrangement of a 24 ft. x 11 ft. 6 ins. hatchway; the 
coamings were 30 ins. high and 4%; in. thick. There were two web beams, % plate with 8 x 3 x 2 double 
mounting angles. On top of these beams were three wood fore-and-afters, 6 x 6 ins. square, giving an 
unsupported span to the wood covers of 2 ft. 74 ins. (the present minimum requirement is 22 in. 
covers with an unsupported span of 5 ft.). 


| 


In 1889 the rules for the building of steel ships was first published; the hatchway rules, however, 
for both the iron and steel ships remained the same, except for the minor addition that wood covers were 
not to be less than 24 to 3 ins. in thickness. 


In 1901 the rules were considerably amplified, the relevant items regarding hatchways being :— 


Sides. Ends. 
Thickness of coamings, under 12 ft. long ... ies a ay 
5 _ 12 ft. and under 16 ft. ... sy 30 
- - (eft to OE fe a 2s Ss 
The minimum height of coamings on the weather decks :— 
On shelter, bridge, awning and part awning decks a2 18 ins. 
On upper, spar and raised quarter decks... be ae 24 ins. 
On upper deck in wells of well deck steamers... 30 ins. 


All coamings on weather decks were to be of steel or iron. Hatchways 12 ft. in length and under 
were to have shifting beams formed of bulb plate and double angles, or equivalent bulb tee. If the 
width of hatchway was less than 12 ft., the shifting beams were to be 8 x .8,, and if from 12 ft. to 16 ft. 
in width 9 x .%. When the length of the hatchway was from 16 ft. to 20 ft., a web plate beam was to 
be fitted at the middle of the length, extending in depth to the lower edges of the coamings; above 
20 ft., and not exceeding 24 ft., two web plate beams to be fitted. 


A table showing the number and scantlings of steel fore-and-afters was given for the first time, the 
scantlings being based only on the breadth of the hatchway. Wood fore-and-afters could be adopted if 
iron plates were fitted to the ends, and end bearings were not to be less than 2 ins. Plans of hatchways 
more than 24 ft. in length or 16 ft. in breadth, showing proposed scantlings were to be submitted. All 
hatches were to be solid and not less than 2} ins. to 3 ins. in thickness; efficient supports were to be 
provided, and bearings at the ends of the hatches were not to be less than 1} ins. Cleats not more than 
2 ft. apart from centre to centre were to be fitted to the coamings for the purpose of efficiently securing 
the tarpaulin covers. Flat iron bars and suitable wedges were to be provided for securing the tarpaulins, 
and securing bars were to be fitted for securing the hatches. In vessels having self-trimming hatches, 
wing boards were to be fitted for preventing the shifting of cargo. 


In 1908 the rules were further amplified by extending the tables for the scantlings of steel fore-and- 
afters and also including scantlings for wood fore-and-afters; the latter were to be of pitch pine or other 
wood of not less hardness and strength. Tables were included for the first time showing the scantlings 
of web plate beams without fore-and-afters, also when this arrangement of web plate beams was adopted 
the hatches were to be solid and not less than 3 ins. thick. 


In 1909 the table for fore-and-afters, both wood and steel, was amplified and this time for the first, 
account was taken of the span of the fore-and-after as well as its spacing in arriving at its scantlings. 
The noteworthy alteration, however, throughout the rules for this year was the change over in giving 
thicknesses in decimals instead of in vulgar fractions. The wood for the fore-and-afters was further 
specified to be free from shakes and other defects; and the centre fore-and-afters (those with the ridge) 
were to be cut from the solid wood. 


In 1911 the table giving the thickness of the coamings was extended to include hatchways 30 ft. 
long and the thickness in this case was to be °50 for the sides and *40 for the ends. Regarding the 
requirement for larger hatchways, plans were not required to be submitted until the hatchways exceeded 
30 ft. in length and 16 ft. in width. 


In 1915 another complete revision took place, and the amendments then made conformed with 
proposals suggested by the Load Line Committee. In brief these were :— 
Minimum height of coamings, 


On upper, awning and raised quarter deck where exposed to the weather... were) Bae ITiB, 
On decks of superstructures where exposed to the weather within } length from stem 24 ins. 

abaft } length from stem 18 ins. 
On decks within open superstructures ... a 3f: ws aa oo ; 18 ins. 
On decks within superstructures which have means of closing “on ads =. 9 ins, 


On 


On decks below upper decks or within intact superstructures, coaming plates were not required, 
angles being sufficient. 


Coamings of hatchways on upper or superstructure decks were to be *44 thick ; coamings of 
hatchways below upper decks or within intact superstructures, sides ‘50 and ends °40. 


Hatchway side coamings, not less than 24 ins. high, were to be stiffened near the upper edge with a 
horizontal bulb angle not less than 7 ins. Plans were to be submitted when the length of the hatchway 
exceeded 30 ft. and the breath 20 ft. Scantlings for web beams and fore-and-afters were now divided 
into two tables : (A) so spaced that the unsupported length of the hatch covers did not exceed 4 ft. 6 ins. 
in all hatchways, except in the following cases (a) exposed hatchways of a superstructure abaft } length, 
and (b) hatchways in spaces fitted exclusively for the accommodation of passengers where they may be as 
per table (B) with unsupported length of cover not exceeding 5 ft. 6 ins.; the thickness of the covers to 
be 2} ins. and in no case was the spacing of the webs to exceed 10 ft. All web beams were to be fitted 
with 7 in. doubling plates at their ends; hatch rest bars on side coamings when fore-and-afters were 
fitted were to be 2} ins. and on end coamings where no fore-and-afters, 3 ins. wide. Cleats 2 ft. apart 
and 6 ins. from the ends, 2} ins. wide and with not less than two rivets were to be fitted on the coamings. 
The battens, wedges and tarpaulins were to be efficient and in good condition. Scantlings for webs and 
fore-and-afters were to be obtained by interpolation and increased when tween deck height exceeded 
8 ft. 6 ins. 


In 1922 a slight modification was made in the thickness of coamings of vessels less than 200 ft. in 
length: thickness of covers was to be suitably increased for wider spacing of beams and was not to be 
less than 3 ins. for a spacing of 6 ft. in Table A. Where height of coamings exceeded 36 ins. plans were 
to be submitted. 


In 1886 the Board of Trade published its first freeboard rules but not until a later date was there 
any mention of hatchway construction. The paragraph was very indefinite, simply stating that ‘ the 
weather deck hatchways were to be properly framed with substantial coamings, and strong hatch covers, 
the latter being efficiently supported by shifting beams and fore-and-afters suitable to the dimensions of 
the hatchway.” 


For many years prior to 1932 the lack of uniformity in international freeboard assignment was 
apparent, but in that year after many conferences, agreement was reached between the representatives of 
practically all the maritime nations, and the Board of Trade issued “Statutory Rules and Orders, 1932, 
Merchant Shipping (Safety and Load Line Convention) Act” or better known as The Freeboard 
Convention Regulations. These contained, in great detail, the requirements for hatchway construction 
and coyerings, compliance with which was necessary before a new vessel could have a freeboard certificate 
issued. 


As these are the present day requirements they are given herewith and a sketch of a typical 
arrangement of coaming and web beam is shown in Fig. 1. 


The height of the hatchway coamings on the freeboard decks shall be at least 24 ins. above the deck. 
The height of coamings on superstructure decks shall be at least 24 ins. above the deck if situated 
Within a quarter of the ship’s length from the stem, and at least 18 ins. if situated elsewhere. 


Coamings shall be of steel, shall be substantially constructed and, where required to be 24 ins. high, 
shall be fitted with an efficient horizontal stiffener placed not lower than 10 ins. below the upper edge, 
and with efficient brackets or stays from the stiffener to the deck, at intervals of not more than 10 ft. 
Where end coamings are protected, the Assigning Authority may modify these requirements. 


Covers to exposed hatchways shall be efficient, and where they are made of wood, the finished 
thickness shall be at least 2% ins. in association with a span of not more than 5 ft. The width of each 
bearing surface for these hatchway covers shall be at least 24 ins. 


Where wood hatch covers are fitted the hatchway beams and fore-and-afters shall be of the scantling 
and spacing given in Table 1 where coamings 24 ins. high are required, and as given in Table 2 where 
coamings 18 ins. are required. Angle bar mountings on the upper edge shall extend continuously for the 
full length of each beam. Wood fore-and-afters shall be steel shod at all bearing surfaces. 


The Tables L and 2 give the scantlings of the webs for a breadth of hatchway from 10 to 30 ft. 
and for a spacing of webs from 6 to 10 ft., scantlings for intermediate spans and spacing being obtained 
by interpolation ; the Tables also give the scantlings for steel and wood fore-and-afters. The depths given 
for the webs are at the middle of the length. For ships not exceeding 100 ft. a reduction in the depths 
of the webs of 40 per cent can be made and for ships between 100 and 200 ft. the sizes can he 
determined by interpolation. 


Carriers or sockets for hatchway beams and fore-and-afters shall be of steel at least } in. thick, and 
shall have a width of bearing surface of at least 3 ins. 
Strong cleats at least 25 ins. wide shall be fitted at intervals of not more than 2 ft. from centre to 
centre; the end cleats shall be placed not more than 6 ins. from each corner of the hatchway. 
(a) Battens and wedges shall be efficient and in good condition. 


(b) At least two tarpaulins in good condition, thoroughly waterproofed and of ample strength, 
shall be provided for each hatchway in an exposed position on freeboard and superstructure decks. 
The material of the tarpaulins shall be guaranteed free from jute,and the minimum weight of the 
material, before treatment, shall be 19 ozs. per sq. yd. if to be tarred. 18 ozs. per sq. yd. if to be 
chemically dressed or 16 ozs. per sq. yd. for black oi! dressing. 

At all hatchways in exposed positions on the freeboard and superstructure decks, ring bolts or other 
fittings for lashings shall be provided. 

Where the breadth of the hatchway exceeds 60 per cent of the breadth of the deck in way of the 
hatchway, and the coamings are required to be 24 ins. high, fittings for special lashings shall be provided 
for securing the hatchway covers after the tarpaulins are battened down. 

In 1933 Lloyd’s Register amended its rules, regarding hatchways, to agree with the statutory rules ; 
very little alteration, however, was required as the Convention rules practically were what Lloyd's 
Register had been applying since 1915; some of the items given by the latter are in greater detail than 
that contained in the Convention rules, the principal amplifications being as follows :— 

The thickness of coamings are given—for vessels 200 ft. and above, side and end coamings on upper 
and superstructure decks to be *44, for vessels up to 100 ft. °36, and for vessels of intermediate 
length the thickness to be found by interpolation. 

Coamings on decks below upper decks or within intact superstructures to be 40. 

The horizontal bulb angle stiffener on the coamings to be not less than 7 ins. in depth. 

The depth of the hatch webs at the ends to be one half of the depth at the middle, but in no case 
less than 6 ins. E 

The ends of the web plates to be flushed up on each side by doubling plates, of the same thickness 
as the mounting angles, and at least 7 ins. wide. 


As might be expected, departures from the statutory arrangements have been proposed and 
approved, but in every case the equivalent standard of strength and security has to be maintained. 


SOME OBSERVATIONS ON THE STATUTORY ARRANGEMENT OF WEATHER Deck HATCHWAYs. 


The first fact which confronts us in a consideration of the present arrangement of closing the 
hatchway openings in the weather decks of vessels with wood covers and tarpaulins is that the arrange- 
ment, with some slight modifications, is, and has heen the universal practice for centuries. It presents 
some advantages in the facility with which renewals or repairs can be effected, inasmuch as wood for 
hatch covers is obtainable at all ports of call and new tarpaulins can be got at most of the larger ports. 


The objections are numerous, the principal ones are given herewith :— 


1, Harcn Beam SHors.—The hatch beam shoes or slide angles which are fastened to the inner 
surface of the coaming project into the hatchway opening and cause serious damage to the cargo when 
it is being loaded or discharged. This objectionable feature has been apparent for a long time and has 
been partly remedied by the substitution of dished plate shoes or sockets. These sockets are sometimes 
made of cast steel and often get broken with the cargo striking against them. 


5 
‘ 


This objection, of course, is not detrimental to seaworthiness but the arrangement is conducive to 
such, that is, in either type of shoe, dirt and solids collect at the bottom of the shoe and so prevent the 
web beam from housing properly, thus throwing the upper edges of the beams out of alignment. 


2. Haren Brams.—In hatchways which have more than one web beam, the alternate beam has the 
web plate projecting above the heels of the upper mounting angles so as to form a stop for the wood 
covers which usually span two bays, the intermediate or plain-surfaced beam giving support at the mid 
length of the cover. It seems incredible that these intermediate hatch beams should sometimes be 
forgotten to be fitted. Numerous writers have testified to their omission and to their being found in the 
“tween deck spaces. The writer once attended a small vessel which had nearly completed discharging its 
cargo and on looking down the hold saw one of these beams securely lashed to the pillars on the centre line. 


Frequently, when the nature of the cargo permits, the intermediate beams only are removed so as to 
facilitate the rapid closing of the hatchways when loading or discharging has finished for the night, and 
with limited deck space these beams are sometimes put ashore. Cases are known, especially when work 
has been completed in the darkness, of ships proceeding to sea leaving the intermediate beams on the 
quayside. 


As mentioned before, the presence of obstruction in the shoes or sockets prevents the web beams from 
fitting into their places properly and throws their upper edges, or what should be the three points of 
support for the wood cover, out of alignment. If the beam which has not housed properly is at the end of 
a cover the unsupported length is doubled and, of course, the resultant stress is quadrupled. If the beam 
at the middle is too high a see-saw motion is created when the seas roll over the hatches, and the ragged 
ends of the wood covers are liable to chafe holes in the tarpaulins. 


The fatigue which the wood covers are being subjected to may appear exaggerated but the minimum 
thickness of a hatch can be 22 ins. and with a number of 3 in. binding bolt holes transversely through it, 
there is not much wood left to resist stresses which are four times greater than were intended to be applied. 


3. Fore anp Arvrers.—The fitting of fore and afters is, with very few exceptions, confined to 
comparatively small hatchways. Wood fore and afters require more attention than those made of steel, 
the centre ones especially, as the shoulders on which the ends of the wood covers rest become rounded 
and with the ends of the covers also becoming rounded, a proper rest cannot be obtained. Aware of this 
eventuality, some owners require small section angle bars to be fitted heel upwards, at the corner of the 
shoulder in order to maintain the required breadth of landing for the cover. 


1. Woop Covers.—The writer is not an authority on timber but to anyone who is, it must appear 
strange that the regulations do not specify the class or quality of timber to be used in the making of 
hatches ; the only reference to such is seen in the * Instructions to Surveyors” issued by the Board of 
Trade and is that * the wood must be of satisfactory quality, straight grained, and reasonably free from 
knots, sap and shakes, 


The wood usually used for the making of hatch covers is called “ Pinus Sylvestris” otherwise known 
as white, red or yellow pine; it comes from the Baltic and White Sea ports, in four or five different 
qualities, the poorer grades being known as “ Unsorted” or “Millrun.” Most of the poorer quality is 
fast. grown, consequently is course and open grained and is rarely shipped in the seasoned condition; it 
is generally used for ceiling, cargo battens, shifting boards, partition bulkheads and dunnage. Its cheap- 
ness, being about half the price of the better quality, induces many persons, wilfully or in ignorance, to 
use it for hatch making. A superintendent* of a well-known shipping firm, writing with regard to this 
subject of woods for hatch covers stated “that if the Classification Societies were to exercise the same 
control over the materials of which covers are made as they do over the steel of which the ship is made 
and which bears the Society’s stamp, less would be heard of the inefficiency of the wood cover.” The 
observation is perhaps a bit severe but it is not without its significance. 

Reference is sometimes made to covers being “ floated-off”; this statement would appear to be some- 
what erroneous, as it is difficult to understand how a wood cover can float off if there is no water below 
it; however, it could happen, and this is vouched for by the master of a vessel who actually saw the 
occurrence. When a heavy cross sea strikes the side coaming, the latter is deflected to some extent and 


*Capt. R. E. THOMAS on “Harcu Covers” read to the Honourable Company of Master Mariners. 


& 


the wood covers (especially the single plank ones, which have been fairly closely fitted together) under 
the side pressure from the coaming are forced upwards and so tear the tarpaulins, the next or subsequent 
seas complete the disaster. Another result from seas striking the side coamings is the distortion produced 
in the end coamings, that is, they are bulged outwards. 


Hatchways which have an even number of webs have an odd number of spaces; this means there 
will be one, two or more sections of long plank covers and one section of short plank covers; the short 
planks are almost always ended against the end coaming ; these planks, therefore have only two points of 
support and when the end coaming is bulged sufficiently far out there is a possibility of the covers 
dropping into the hold. It may appear that the writer is magnifying this eventuality but it has been 
his experience on occasions when examining covers to push these short covers back from the end coaming 
until they stopped against the extension plate of the hatch web and if they did not actually drop into the 
hold they had only the minimum of bearing surface left. It might be added that this bulging out has 
only been observed on end coamings which were not stiffened with horizontal bulb angles, and this is 
permitted when end coamings are protected by deck houses, etc. 


The wood for the making of hatch covers, when not properly seasoned, shrinks considerably; 
attemps have been witnessed, in the case of single plank covers which, no doubt, fitted closely when the 
ship was new, to close up the covers with a view to fitting an extra one; but if this were not possible 
nothing at all was done, the covers just being equally spaced again: a total gap of anything up to nine 
inches could be a possibility. Some covers also warp badly and split, corners become rounded and the 
piece of wood in way of the hand grips invariably falls out. Fig. 17 shows a typical example of the 
dilapidation which takes place with hatch covers. The covers, unfortunately, also provide excellent 
material for the making of stagings and shutes for the stevedores and coal trimmers, and although this 
usage is against regulations in Britain it is not always so in foreign countries. 


5. TaRPAULINS.—It will be realised, of course, that before water can enter a hold via the hatchway 
the tarpaulins must fail as these are the seal to watertightness. It is important therefore that they 
should be placed in position accurately and battened down securely ; they are heavy cumbersome things to 
man-handle and before they can be battened down they have to be pulled and stretched about into 
position. 

{t is observed that some attention has been given to this important item in the Convention rules ; the 
minimum weight, per square yard, of the material before treatment, is now specified to be according to 
how the material is dressed ; there are also instructions that, in case of new ships, the tarpaulins are to be 
water tested. 


Considerable damage to cargo by rain or sea water can be caused by leaky or defective tarpaulins : 
also if they are thin they can be easily torn by the seas during heavy weather and the vessel can be in 
danger immediately. 


6. Barrentnc WepeEs.—It is possible that battening wedges are not always fitted properly in their 
cleats, that is, with the grain of the wood nof parallel to the coaming (see Fig. 2). It is seen that if the 
grain is parallel to the coaming, there is, with each blow of the hammer, a tendency for the wing of the 
cleat to sheer off the toe of the wedge and its angular effect is lost as it is driven further home; a badly 
aimed blow which strikes the toe of the wedge can also remove this part. Such defective wedges are not 
uncommon on some ships. 


Wood wedges when supplied by the ship builder or repairer are generally made of elm or birch ; they 
are tough and not pronounced as regards grain but as these gradually get lost and are replaced by the 
carpenter, he more often than not uses old hatch covers, the wood of which has a very pronounced straight 
grain and is most easily split. This “demerit” only applies when parallel cleats are fitted; in the later 
types of angle lug cleat which are set at an angle to the coaming the wedge can generally be driven up 
tight. In Fig. 2 “A” shows the wrong way to fit a wedge and “B” the correct way. 


7. Barrentne Cieats.—The ordinary hatch coaming cleat is a casting and is subject to being 
broken by cargo striking it ; the flange or wing taking the wedge is parallel to the coaming. Perhaps when 
this was designed two wedges were intended to be used but two wedges are never now fitted, consequently 


- 


9 


the single wedge suffers damage as just previously explained. Some of the later types of this cleat are 
made of pressed steel plate and in order to avoid the damage to the wedge and to give it a better grip, the 
flange is slightly rounded. 

The usual way of driving a wood wedge into a cleat is :— towards the centre line of the ship on the 
end coamings, towards aft on the forward side coamings and towards forward on the after coamings. 
This arrangement is, of course, to prevent the seas from washing the wedges out of the cleats (see 
B. T. Ing. re * Y,” a primary cause of loss of the ship was due to this occurrence). 

The setting of cleats at an angle to the coaming is, therefore, to be preferred as the wedges can always be 
driven up tight and with the lug cleats on the horizontal stiffeners this is easily accomplished (see Fig. 3). 
The Board of Trade, in a circular on coal-carrying vessels, strongly recommend this arrangement, but 
now it is being suggested that these Ing cleats should be set so that the thick end of the wedge is alter- 
nately facing forward and aft (see Fig. 4); this is to prevent the possibility of a following sea washing the 
wedges out. 

As practically 90 per cent of all the seas which come on board a ship come from forward, it is doubt- 
ful whether this suggested arrangement is advisable, at least for the forward hatchways. Following seas 
are not, as a rule, so violent as head-on seas and the suggestion to reverse every alternate wedge to prevent 
its being washed out must also be an admission that these same wedges, when a violent forward sea does 
come on board, will be washed out, leaving the effective wedges at a spacing of double the rule spacing ; 
and this happening in nine cases out of ten, it is thought that the possibility of the other wedges being 
slackened back and the cargo being damaged by water is too great. There is also another objection to 
this arrangement; when a wedge facing one way is being hammered up, owing to its contact with the 
battening iron, the adjacent wedges facing the other way can be slackened back. 


The wrapping round and lapping over of the tarpaulins at the corners of the hatchway makes many 
thicknesses and this is not always borne in mind by the shipbuilder; the result is that the corner cleat 
wedges cannot be inserted as far as the others and are therefore more liable to be washed out. Some 
builders take the precaution, however, of fitting a packing piece so that the first cleats from the corner 
are one inch further away and the second cleats half an inch further away from the coaming plate than 
the remainder. 


8. LasHtnes.—In recent years the most controversial point in the security of hatchways has been 
the fitting or omission of lashings. Many shipowners who know their job perfectly well simply detest 
lashings because of the destruction they cause to the tarpaulins. It is. nevertheless reasonable to think 
that some fitment shouid be provided to prevent the tarpaulins from ballooning with every gust of wind 
which blows down the ventilator, yet the rules do not specifically state that lashings are to be fitted. 


It might have been that there was some disinclination on the part of Load Line Committee to define 
this requirement; considering it better simply to ask the shipowner to provide fittings for lashings and 
leaving the fitting of the lashing to the master’s discretion. 


Within recent months the writer was on board a five-hatchway cargo ship and discussing hatchways 
in general with the chief officer asked him how he fitted lashings; he replied that he was not quite sure 
as in all the ships he had been, lashings had never been fitted. The Convention Regulations have now 
been in force for over three years. 


It appears from the foregoing that the “demerits” of the orthodox system of hatchway construction 
and arrangement are numerous. Although each item in itself may be small, yet collectively they are of 
major importance to the safety of the ship, and it is absolutely essential they should always be efficient 
and effective. It is obvious that the system is dependent on a great many components, such a small item 
as a bad or badly fitted wedge coming adrift may lead to the adjacent wedges being washed out of the 
cleats, the tarpaulins flapping about and tearing, and finally the wood covers becoming dislodged and the 
possible foundering of the ship. 

A not unnatural question might now be asked how is it that vessels have survived all these years 
with this apparently very inefficient arrangement. The answer can only be that the strictest attention 
has had always to be paid to every component in the system, otherwise, when the test of heavy weather 
came to be applied, catastrophe could have been inevitable. 


10 


Boarp or TRADE OFFrIctraL Inquiries Into Losr VESSELS, THE CAUSE, IN SOME MEASURE, BEING 
CONSIDERED DUE TO HarcH FAtLure. 


In an examination of the reports of all the Board of Trade official inquiries held since 1918 on 
British vessels lost, stranded or destroyed by fire, it was seen that quite a number of ships foundered, 
the cause, either main or contributory, being ascribed to the inefficiency of the weather deck hatchway 
coverings. In many cases all hands went down with the ship, which, besides being tragic, was 
unfortunate from the point of view that no direct evidence could be obtained as to the nature or 
sequence of events which led’ to the disaster. 


In those instances when there were no survivors, nor wireless messages, the cause of the foundering 
has been a matter of conjecture, but reports of heavy weather about the same time and place as the 
vessels were last seen or heard, and other considerations, have given the Courts the opinion that the 
hatchway coverings, in failing to keep out the seas, were the cause, in varying degrees, of the ship being 
lost, and practically every time accompanied by loss of life. 

Abbreviated accounts of those cases of foundering in which the failure of the hatches has been 
considered to be, directly or indirectly, the cause of the loss is given in the Appendix. A list of the 
vessels is given herewith, showing the nature of the casualty and the salient points which were brought 
out at the inquiry :— 

... Hatches burst in by heavy seas. 

-.  Tarpaulins chafed through at the coamings by the deck cargo, permitting the seas 
to enter the hold. 

Tarpaulins of bunker hatchway torn and washed off; accumulation of water in 
boiler room extinguished fires. 

Tarpaulins turned back for ventilation, naked light ignited petroleum vapour in 
hold and caused explosion. 

Self-trimming collier. Tarpaulins torn and split and wood covers washed away. 
Tarpaulins, although in good condition, considered defective in strength. 


nm OO Bd 


.-.  Self-trimmer. Breaking of the wood covers or tarpaulins. The Court considered 
a more effective method of securing tarpaulins than by lashings would prevent 
them splitting and tearing. 


G_... _— Main hatchway stove in. 

H General condition of the vessel, including the hatchways, in a bad state of repair. 

J... ‘To prevent probable damage to tarpaulins by deck cargo of pit props, tarpaulins 
not fitted on hatchway ; vessel listed and water entered hold. 

K_... Wireless message “hatches going.” The Court made special reference to 
inefficiency of present design of hatchways and recommended an investigation 
with a view to producing a stronger hatch cover. 

L... — Self-trimmer. Covers and tarpaulins broken in. The Court considered that the 
large areas of hatchways were equivalent to a loose or portable deck. 

Self-trimmer. Tarpaulins ripped and wood covers lost. The Court considered 
that the wooden hatches were equivalent to a portable deck. 

ING: Self-trimmer. Cause unable to be determined. Considered that with exceptionally 


large hatchways, it is absolutely necessary that the security of the hatchways 
should be well looked after. 


O_... ___ Battens and wedges washed out and tarpaulins stripped. Court recommended better 
type wedges should be fitted and a suitable number of locking bars. 
...  Self-trimmer. Hatch covers smashed. The Court is of opinion that these large 
hatchways are a positive source of danger. 
R_... — Tarpaulins and wood covers washed away. 


11 


Ss ... Self-trimmer. Wireless message * hatches stove in.’ Some wood covers after- 
wards found and examined. The Court considered they lacked in strength and 
that stipulations should be made specifying timber for hatches, also that the 
question for the use of steel in the construction of covers should be considered. 

T ~~ ... Unsecured hatches over short after well, which had high bulwarks, carried away. 

U_... —_ Hatchway coamings buckled, web beams set down on to the cargo, wood covers 
broken and washed away. The structure of the hatches, and whether they 
should have been of steel rather than of wood was a subject of argument by the 
Court. 

Ve... No. 1, 2 and 5 hatches stove in” per wireless message. There was much 
conflict of evidence as to the covering and security of the hatchways and the 
condition of the covers and their fittings. 

W_... Wireless messages “ water entering No. 1 hold” and “after hatch stove in”. The 
Court records that with regard to the hatchway coverings, they were as one 
might expect to find in a ship of her age, that is, they were not new but 
sufficient and adequate for the voyage. 

xX ~~... Cause unable to be determined. Possibility of a hatch failure, regard being paid to 
the fact that several recent casualties can be ascribed largely to the failure of 
hatches. 


Y ...  Self-trimmer. Wholesale washing out of the wedges and tarpaulins from the 
coaming cleats. The President criticised severely the so called self-trimmer and 
added that the menace to the safety of the crew was very grave in such craft. 


It may be considered by some that the above number (23) of cases, is small in relation to the long 
period over which the review has been made, but it should be borne in mind that those are only the losses 
into which inquiries have been held, and of course are only of British ships. The Load Line Committee 
found in its investigations that 13 per cent of vessels lost were due to hatch failure. The total number 
of casualties due to this cause for ships of all nationalities must be quite extensive. 


Of the 23 cases examined, the Court had to deplore the fact that 10, or about one-half of them were 
lost “with all hands,” whilst eight, or about one-third of them, were self-trimming colliers. The 
Court’s opinion in the case of P “that these large hatchways are a positive source of danger”. is 
worthy of note. 


In the examination of the full accounts of the fore-going reports one rarely finds any evidence that 
anyone actually saw wood hatch covers being broken by the force of the seas falling on them. In cases 
without survivors, wireless messages have been received stating “ hatches stove in” but it is not certain 
whether this is literal or simply a phrase indicating that the hatch coverings had failed, probably the 
latter ; yet the courts in such cases and also in cases where no messages had been received ; very often, 
after due deliberation, find that “the loss of the ship was due to heavy seas breaking or bursting in the 
hatches.” 

In contrast to the above, when survivors have been available their evidence invariably shows that the 
first trouble experienced with the hatchway has been with the tarpaulins either being split or being 
washed out of the cleats, then the wood covers become dislodged and are washed overboard, water eventually 
finding its way below. 


It would therefore appear, and it is generally agreed that the wood covers are amply strong for their 
job; but the tarpaulins, these items which form the watertight seal to the spaces below are the least 
satisfactory links in this system and unfortunately, up to the present, nothing practical has been 
suggested as a substitute for the tarpaulin. The tarpaulin at its best is a cumbersome and awkward 
thing to handle, when new it is stiff and unwieldy and by the time it is more pliable its efficiency is 
waning. One can visualise men on a dark winter night, standing waist deep in swirling water alongside 
a hatchway coaming trying to resecure a thick and stiff tarpaulin which has come adrift, a hammer in 
one hand, a bag of wedges in the other and holding on by their—well the job is almost impossible to 
execute properly. 


12 


It is significant to note that many of the Courts criticised severely the orthodox type of hatchway 
and made recommendations for improvements in various directions in the design, but officially very 
little seems to have materialised from these observations. 


Luioyp’s Datny CasuaLty List. 


A somewhat less tragic but none the less important list from our point of view of hatch failure is 
also given in the Appendix. It consists of extracts from Lloyd’s Daily Casualty List for the past year 
of those vessels reporting damage to hatchways. Lloyd’s List reveals practically everything which 
happens to ships all over the world whether at sea or in dock; from the dry docking of the “* QUEEN 
Mary” to the capsizing of a small boat on the China Coast, and to give a percentage figure of the 
number of vessels reporting hatch damage to the total number of vessels reporting damage of any kind 
could not be considered a comparison having any real value. The underlying object in compiling this 
list, however, was to show that damage is being received frequently to an important part of the 
ship’s structure. The cause of this frequency, in the opinion of the writer, is that although during the 
last 50 or 60 years the size of hatchways has increased, little or no progress has been made towards 
providing them with better coverings. 


The damages, as reported in the List, may be trifling or serious (their extent is not always given), 
but it is easily conceivable that nearly every case could have been the beginning of a serious calamity. 
Numerous entries, not recorded here, refer to vessels having encountered heavy weather and receiving 
damage to deck fittings, etc., which damages could also include split or torn tarpaulins or the loss of 
battening wedges. 


QUESTION OF REDUCTION OF FREEBOARD WHERE WATERTIGHT STEEL Harcw Covers Arg Frrrep. 


The more cargo a ship carries the fewer number of ships will be required to carry the world’s 
freight. Asa result of the freeboard revision in 1932-8, it was reckoned that, in the case of the 5,000 
odd ships which had their freeboards reassigned by Lloyd’s Register of Shipping, due to the extra inches 
of draught which many of them received, something like half-a-million more tons of cargo could be 
carried by the same number of ships; it would appear, therefore, that to suggest a further increase of 
draught would not be sound policy. 


There is, nevertheless, in the 1932 Convention Freeboard Rules a paragraph which permits vessels, 
other than tankers, to load deeper than the ordinary tables permit; a recital of this particular paragraph 
may be of interest to those who are not already familiar with its existence. 


“Paragraph 109.—In the case of steamers of special type over 300 ft. in length possessing 
constructional features similar to those of a tanker, which, in the opinion of the Board of Trade, 
afford extra invulnerability against the sea, a reduction in the freeboard computed for steamers 
under Part VI may be granted. 


The amount of such reduction shall be determined by the Board of Trade with reference to the 
freeboard assigned to tankers, having regard to the extent to which the steamer complies with the 
conditions of assignment and with the requirement of Part IX of these rules and the degree of 
subdivision provided in the ship, but the freeboard assigned to such a ship shall in no case be less 
than the freeboard which would be assigned to her if she were a tanker.” 


When the question of deeper loading for tankers was being considered by the British Load Line 
Committee, according to its report published in 1929, a point which influenced it greatly was the fact 
that tankers owned in the United States of America had, for some considerable time, been loading very 
much deeper than would have been permitted had they been owned in this country, and that no serious 
consequence had befallen them on account of this deeper loading. 


A considerable amount of evidence was obtained from both American and British shipowners and 
ship masters, and the information which was collected from the American owners showed that in actual 
practice the average percentage reduction from the British freeboards, on all voyages, was over 20 per 
cent. Considerable discussion took place over the question, but as “the proof o’ the puddin’ was the 


13 


preein’ o° it,” the Committee finally agreed that deeper loading could be permitted but the amount was 
to be left for international decision. Since the reassignments took place some three or four years ago, 
there is no indication that casualties to tankers have increased or that casualties which have occurred 
have been caused by deeper loading. 

The Committee in their report stated that “our main ground for accepting the principle is the 
efficient protection provided for openings in weather decks by means of steel watertight covers. It 
seems to us that this protection—vital in its importance—considered in conjunction with other 
characteristic features of tankers, gives sufficient justification for preferential treatment of tankers in the 
assignment of load lines.” 

In order, however, that the special type vessel (i.e., paragraph 109) might obtain the minimum 
freeboard according to the tanker tables, she must comply with certain supplementary conditions which 
are compulsory for, or incorporated in, the construction of a tanker; these are :— 

1. The structure of the ship shall be of sufficient strength for the increased draught. 

2. ‘The ship shall have a forecastle not less than 7 per cent of the length of the ship and 
height not less than standard height. 

3. Openings in machinery casings to be closed by steel doors, the casings to be closed by a 
poop or a bridge, entrances of which to have effective closing appliances, etc. 

4. Fore and aft gangways to be fitted at level of superstructure decks for access of the crew. 

5. Safe access from gangway level to crew’s quarters, etc. 

6. All hatchways on freeboard deck and on the deck of expansion trunks shall be closed 
watertight by efficient steel covers. 

7. Ventilators to spaces below the freeboard deck shall be of ample strength or protected by 
superstructures. 

8. Bulwarks shall have open rails for 50 per cent of the exposed length of the weather deck, 
and where superstructures are connected by trunks, open rails shall be fitted for whole length of 
exposed weather deck. 

As the main ground for accepting the principle of deeper loading for tankers was the efficient 
protection provided for openings in weather decks by means of steel watertight covers, the same point, 
therefore, is assumed to be the main ground for permitting deeper loading in paragraph 109 vessels. If 
it were feasible to assign a percentage to each of the various items which a vessel must comply with in 
order that she might obtain the increment in draft, in view of the considered importance of the fitting 
of steel hatch covers, a modest, estimate of say 25 per cent, for the purpose of comparison, might be the 
allowance for this requirement. It is recognised, of course, that the attitude of the authorities on this 
question might be that all the requirements should be complied with and no interpolation whatever 
permitted. 


In a contribution to the discussions in one of our previous papers it was stated that * It is very 
desirable to emphasise the general opinion of the Load Line Committee that per se there was nothing in 
evidence to indicate that freeboard was a denominating factor in causing the loss of ships, but on the 
other hand, great attention and yet greater attention should be paid to the protection of openings 
in decks, whether of hatches, ventilators, or other arrangements. ‘The evidence collected by the Load 
Line Committee, and their own personal inspection of ships, clearly indicated that improvement in this 
direction was not only desireable, but necessary. They emphatically endorsed this opinion by practically 
stating that the question of protection of openings had nothing to do with the actual freeboard assigned, 
and they required all these questions to be dealt with not in terms of freeboard, but as a condition of 
the issue of a freeboard certificate. In effect, they would not entertain the arguments that because the 
height of hatchway coamings had been increased the ship should be entitled to reduction of freeboard.” 


This is another instance of attention being drawn to the fact that hatchway coverings are a possible 
source of danger and to the necessity for improvement. The last sentence shows that freeboards could 
not be lessened because of increased height of coamings; this was a very sound decision, but it is thought 
that the question of covering the hatchway openings with steel watertight covers in ordinary cargo and 
passenger ships could be investigated. The writer has no knowledge whether the Committee considered 
this question in relation to freeboard. 


14 


Practically all shipowners are astute business men and refrain from spending any more money in the 
construction of their ships than is absolutely necessary. The fitting of steel watertight covers to four or 
five large sized hatchways is an expensive item, and if the particular type of cover is patented the royalties 
may reach some hundreds of pounds. Before such expenditure could be contemplated the shipowner 
would naturally want to know what financial benefit he might expect from this outlay. 


Let us consider an ordinary cargo vessel, say 400 ft. by 52 ft. by 31 ft. with standard round of beam. 
standard sheer, block co-efficient of °78 and total length of erections, poop, bridge and forecastle equal to 
50 per cent of the length of the vessel. The freeboard in this case would be 745 ins. : for a tanker of 
similar dimensions, form and length of erections, the freeboard would be about 624 ins., or a difference 
in draught of 12 ins. 

Reverting to the previous assumption of 25 per cent being the allowance for the fitting of watertight 
covers then, in the case of the 400 ft. cargo ship, this would represent a 3 ins. increase in draught, and would 
equal about 130 extra tons of cargo being carried each Voyage, some inducement, no doubt, for an owner 
who desires every ton of freight. On first thoughts, this seems very generous to give a 400 ft. ship 3 ins. 
more draft simply because of the fitting of steel watertight covers to the weather deck hatchways ; but in 
a further consideration of the same vessel if 3 ins. more draught is desired an addition of 28 ft. or 7 per cent 
in the length of the erections is all that is necessary. It is assumed that the openings in the bridge front 
are closed with Class I and the openings in the other end bulkheads with Class I closing appliances, in 
order to obtain the full 100 per cent allowance. A minute increase of ‘015 of an inch would be required 
in the thickness of the stringer and deck plating ; the required increase to the framing would not be 
evident. 

The question now seems to resolve itself into, whether the fitting of an extra 28 ft. of erections in a 
400 ft. cargo ship or the closing watertight by steel covers of all the exposed hatchways on the weather 
deck affords the better invulnerability against the sea. The writer considers the latter method has much 
to be said in its favour. 

Officially, it is assumed that the extra 28 ft. of erections gives that extra reserve of buoyancy or 
protection which justifies the extra 3 ins. of draft. The cubic capacity of hatchways is never included 
in considering reserve of buoyancy, but it appears that large hatchways closed watertight afford a better 
reserve of buoyancy than erections which have their end openings closed only by loose shifting boards in 
channels, 

In the paragraph 109 previously referred to, reference is made to “the degree of subdivision 
provided in the vessel.” As freeboards are considered on the geometric form of the vessel and are not 
dependent on the number of bulkheads which are fitted, this subdivision requirement to enable a ship to 
load deeper to the small extent which has just been considered would seem not to apply in this case; the 
fact that she is submerged a further 3 ins. in the water does not render her more liable to being bilged. 
If the degree of subdivision has to approach that of a tanker then the proposition is impossible, as cargo 
ships, except some special type ore carriers, are not so constructed. Nevertheless, it has been pointed 
out that with the classification number of bulkheads in the 400 ft. poop, bridge and forecastle type of 
ship and with a reasonable arrangement of the bulkheads a one-compartment ship could be obtained, 


It is fairly well established that the freeboards assigned to the particular types of ships are the 
minimum which can be allowed with safety; however, when a hybrid ship appears and is, in a seaworthy 
sense, something better than the ordinary type of cargo ship but not so good as a tanker, it might be 
considered admissible if an owner made out a case for his vessel to receive a draught intermediate between 
the basic types. At any rate, every encouragement possible should be given him to produce a more 
seaworthy ship and extra draught seems a good inducement. 


Sevr-TrRImMMING CoLitERs. 


Ever since coal has been transported in ships there comes along periodically someone to point out 
the dangers of employing vessels in this trade or to condemn or criticise the design of the vessels so 
employed. 

With the exception of trawlers, the losses in self-trimming colliers easily lead the field ; trawlers are 
generally lost through stranding, which, in most cases, is attributable to the failure of the human 
element ; self-trimmers are lost. in deep water and the cause, in many cases, is considered to be the 


failure of a creation (i.e., the hatchways) of the human element. Recently at a Court of Inquiry which 
was being held into the loss of one of these so called self-trimmers, the President made some serious 
criticism of this type of ship and added “that the menace to the safety of the crew was very graye in 
such craft, especially where the cargo consisted of small or duff coal.” 

It appears to the writer that these vessels cannot be completely self-trimmed as with coal reposing 
at an angle of 37 degrees, and more in the case of the small washed variety of coal which is very adhesive, 
there is bound to be a considerable empty triangular space underneath the deck, from the hatch side to 
the ship’s side, and from the hatch end to the end bulkhead in the hold, With a beam wind and sea for 
a couple of days it would not be impossible for such a ship to develop a list, in fact many colliers de 
wrive in port with a list. A collier, therefore, in a seaway with a list is in a very precarious position 
as the side coamings of the hatchways can be submerged much sooner than is the case with the ordinary 
cargo ship; the security of the coverings then is of vital importance, 

The trend of this paper is the advocacy of a better method of hatchway covering than the wood and 
tarpaulin arrangement, for instance, the watertight steel cover which does not, require tarpaulins. In 
the ordinary passenger or cargo ship the proposition is feasible and, in fact, has been accomplished to the 
writer’s knowledge in something over 150 ships. In the case of the self-trimmer the proposition is 
difficult owing to the great breadth and large area of the hatchway ; in some cases the areas of these 
openings exceeds 50 per cent of that of the deck, 

Most designers of steel hatch covers try to eliminate the hatch web beams, which arrangement 
necessitates the cover stiffener being of such scantlings as to support the load of the seas falling on it and 
also to prevent any permanent deflection taking place. Steel covers, therefore, for such broad openings 
begin to reach a weight which prohibits their adoption, nevertheless, designers are busy at the moment 
trying to devise systems in which mobility and stowage of the covers can be satisfactorily arranged. 

The problem is, no doubt, difficult, but a suggestion is herewith made which might help in the 
solution ; that the large area hatchway be divided in two, longitudinally. That is, there could be two 
hatchways in the width with about a8 or 4 ft. passage way between them and to further increase the 
self-trimming qualities of the hatchway the outer side coamings which are usually about 6 ft. from the 
bulwarks could be made a foot or so nearer them ; this would lessen the empty space under the deck at 
the side by about one third. Tt is recognised immediately, of course, that loading and discharging would 
not be such an easy job as with the large hatchway. 

The majority of casualties to self-trimmers occur in vessels about 40 ft. in breadth, therefore, with a 
4 ft. centre passage way and two 5 ft. passage ways at the bulwarks, a width of hatchway of 13 ft. could 
be obtained. Loading is generally carried out by the coal sliding down shutes into the hold; with 
a little care in directing the shutes this could be done. Discharging is done either hy elevator, tubs or 
grabs and as neither of these exceed 7 or 8 ft. in a diagonal measurement, the work again with care could 
still be done. 

The fitting of watertight steel hatch covers then would be a very much simplified proposition, even 
if it were not desired to have steel covers, much better control could be had over a hatchway of this area, 
covered with wood and tarpaulins, than one twice its size: wire lashings would be much more effective on 
a span of say 13 ft. than at 26 ft. and according to the Rules extra lashings which are reqtured on broad 
hatchways could be omitted; tarpaulins would be smaller and more easily handled, hatch webs would be 
shorter and lighter and more easily stowed. Another feature of the arrangement is that the space 
between the coamings and the bulwarks would be lessened and consequently the weight of water which 
collects here in heavy weather and does not free itself as quickly as is desired, would also be lessened. 
The centre passage way would be a better means of transit for the crew and steering gear rods would be 
more safely housed here than at the gunwale. 


TonnaGe Wert Harcuways. 

Tonnage well hatchways, of course, are not used in the loading or discharging of the ship, but are 
simply a means, with other requirements, for the ’tween deck spaces below being exempt from tonnage 
measurement. They are referred to in the Tonnage Rules as permanent deck openings, so therefore, to 
be effective, are not permitted to be closed weathertight like the cargo hatchways; a description of them 
might appear to be extraneous to this paper, but as some doubt frequently exists as to their position, 
arrangement and construction it was considered this dubiety to be sufficient reason for their inclusion. 


16 


Although tonnage well hatchways are usually placed at the after end on the shelter deck of complete 
superstructure vessels, they can also be placed at the forward end ; they can, if so desired, be fitted in the 
decks of detached superstructures which have their ends permanently closed ; this, however, is seldom 
done except in the case of a long combined poop and bridge house, 


As before stated, the sole reason for their being fitted is to lessen the dues and tolls which a vessel 
has to pay in port or in passing through canals, and as this reduction can be a considerable amount, the 
various port, harbour and canal authorities exercise every effort to see that the rule which permits of the 
reduction and which means a loss of revenue to them, is carried out absolutely to the letter of the law. 
It is understood that the Panama Canal Authorities are the most stringent in this respect and demand 
the full amount of dues should any minor deviation from the rules be discovered, 


In order to enable a shelter deck vessel to qualify for exemption of the “tween deck spaces in the 
tonnage measurement and also in order to obtain the maximum allowance for these spaces in the freeboard 
computation, the following rules must be strictly observed. 


The tonnage opening shall be not less than 4 ft. long, and this length shall extend for at least the 
width of the after cargo hatch on the same deck. If there is an angle iron rest bar on the inside of the 
coaming, care must be taken to see that it does not extend for the full width of the opening, for in the 
event of the opening being just 4 ft. or a little over, the admeasurer will claim that the 3 in. rest bar 
disqualifies on account of the inside measurement of the opening being less than 4 ft. In such cases a 
few inches cut off each end of the rest bar and a few inches out of the centre will rectify the matter and 
in no way interfere with its purpose to support the wood hatch covers. 


Should it be desired to have rounded ends to the tonnage openings, great care should be taken that 
the curve is not so made that the length of the opening is less than 4 ft. (inside measurement) at the 
point where the width of the opening reaches the outer edge of the after cargo hatch. 


The position of the opening, if fitted aft, must be such that the distance between its after edge and 
the after side of the stern post is not less than one-twentieth of the registered length of the vessel. If 
the opening is situated forward, then its forward edge must not be less than one-fifth of the registered 
length from the fore side of the stem. 


The coaming round the opening shall not exceed 12 ins. in height, and must not have any cleats 
attached to it, but stanchions fitting into sockets riveted to the coaming and a guard rail are required on 
all four sides. As the means of closing must be of a temporary character, the type of socket should not 
be such that 1t can be used as a cleat and so enable a tarpaulin to be battened down. The writer 
recollects a captain, at the fitting out of a new vessel, having such types of sockets removed from the 
coamings and ordinary deck sockets fitted, at least 9 ins. from the coaming. He recalled an occasion 
when he was master of a previous ship on which these coaming sockets lent themselves admirably as 
cleats, and as such were used, very naturally, by the varpenter to batten down the tarpaulin ; the practice 
had gone on so long that no one thought any rules were being infringed until their first visit to the 
Panama Canal. The admeasurer saw the infringement, and the owners had to pay full dues. 


The thickness of the wood covers and their Supports are to be in accordance with the freeboard 
tables for cargo hatchways ; the covers are to be secured by hemp lashings, and this is generally done by 
lacing the lashings through ring bolts fitted on the underside of the covers, As cleats are not permitted, 
tarpaulins are not intended to be used. 


For freeboard purposes the height of the coaming should not be less than 9 ins. 


Tanker Hatcuways. 


Hatchways in a tanker are small and numerous, their size varies, but generally they are’6 ft. by 4 ft. 
with 30 ins. height of coaming, There is no rule for the minimum height of coaming of an oiltight 
hatchway, obviously being oiltight from within it must be absolutely watertight from without; coamings 
as low as 12 ins. in height have been fitted, which makes construction easier and more economical and 
damage from heavy weather less likely, although coaming damage by this cause is rare; British tankers 
do not, as a rule, adopt low coamings. The reason may be attributable to the Factory Act which 


17 


demands that open hatchways when not being used in loading or discharging and which have coamings 
less than 30 ins. shall be fenced to a height of 8 ft. The maintenance of and the time involved in fitting 
and dismantling portable stanchions and chains around each small hatchway does not evidently justify 
the fitting of low coamings. 


Although the hatchway may be rectangular in shape the opening in the deck plating must have well 
rounded corners, Some builders prefer not to cut the beam either longitudinal or athwartships which 
passes across the opening, and while this cannot be a hindrance to cargo it limits the size of receptacle 
which has to be lowered into the tanks when cleaning out of sediment is in progress. 


The hatchway covers or lids are always fitted with ullage holes, these have circular frames with a 
6 in, screwed plug in them, They must be opened when pumping is in progress ; they are also used 
When measuring the level of the oil and when samples are being taken; in connection with this latter 
operation it is essential that they should not be fitted immediately above the ladder as a sample of oil is 
always taken from the bottom of the tank. 


Oiltightness is effected by the fitting of greasy hemp, about 1} ins. sq.; sometimes it is fitted on 
the coaming protruding slightly above the top edge; the better method, however, is to fit it in a 
small section channel around the periphery of the cover, the top edge of the coaming making contact 
when the coyer is closed. 


Toggles. 6 ins. from each corner and 15 ins. spacing are fitted around the cover, with butterfly nuts 
a perfect oiltight joint can be made. If properly made hinges are not fitted ; two of the toggles at the 
inboard side of the cover, with a nut above and below act as hinges ; struts for keeping the cover in a 
half open position are often fitted. 


Tankers, because of the nature of their cargo, are considered to be sluggish and consequently are 
wet. Fig. 48 shows a tanker in a seaway and gives one an idea of what these vessels, semi-submarines 
one might call them, look like in rough weather. Owing to the covers being of steel, the anxiety to 
those on board regarding the possibility of having hatches stove in, must be reduced to a minimum. 


WELDING IN THE ConsrrucTION oF HarcHways. 


As the more modern method for making the connections of steelwork in vessels is by welding 
instead of by riveting, approval has also been given to this means of fastening in hatchway construction. 
The making of hatch web beams has therefore been simplified, as three strips of plating only are now 
required, one web plate of tabular thickness and two comparatively thicker plates as flanges. The 
connection between web and angle flanges in the normal case being by rivets 7 diameters apart, inter- 
mittent welding is required in the new method, although several shipbuilders prefer to make this 
connection with a continuous run of welding on each side of the web. 


A previous deterrent to the fitting of steel watertight hatch covers was their excessive weight ; by 
the adoption of welding many of the connecting angles can be eliminated, and by reversing the angle 
bar stiffeners so that the toes of the longer flange can be welded to the plate cover, a very much lighter 
cover can be produced, 


The connection of the hatchway coaming to the deck plating is considered an item of primary 
structural importance, therefore electrodes classified in this category must be used. 


STRENGTH OF STEEL Harcu Covers. 


The question of the strength of steel watertight hatch covers cannot be dealt with at this stage, as 
finality with the authorities has not yet been reached. Previous to 1932, there being no statutory rules 
for hatchways, the approval of arrangements and scantlings rested with the classification societies with 
whom the ships were classed. Lloyd’s Register have had for a number of years a practice and standard 
which up to the present time seems to have been adequate, as no reports of failure have yet heen 
received, 


18 


The present freeboard Convention Regulations do not specify any rules for steel covers, but apparently 
there is an inference that any type of cover shall be equivalent to the standard laid down in the tables, 
This means that an arrangement which incorporates hatch web beams, these beams, naturally, shall be 
as per the tables; but, when hatch beams are dispensed with, the question which arises and awaits 
decision is, can a system employing a comparatively large number of closely spaced stiffeners securely 
attached to the cover plating be comparable to a system which has a small number of large widely spaced 
beams and only covered with loose wooden planks ? 


STeEL Hatch Covers aS A MEANS oF LOCALISING A Fire. 


The hatchways referred to, so far, have been those which are exposed to the seas and which are 
required by the regulations to be closed and battened down with wood covers and tarpaulins; they are 
generally known as the weather deck hatchways and the contention of this paper is that vessels which 
have these hatchways closed with steel watertight covers are more seaworthy than those whose 
hatchways are covered with wood and tarpaulins. In vessels with ‘tween decks the hatchway coverings 
are only required to be strong enough to support the weight of cargo which rests on them, battening down 
gear not being necessary. 


In open shelter deck vessels, however, the first tween deck is regarded as a weather deck, in that 
the freeboard is measured from this deck and therefore the hatchways must be closed weather-tight 
similar to those on the exposed decks ; the same requirement also applies to the upper deck hatchways within 
superstructures whose ends are not closed watertight. To suggest that those hatchways should be closed 
with steel watertight covers for their protection against the sea would be stretching the point too far; but 
there is another reason why such covers could be fitted with advantage in these spaces, and, in fact, on all 
lower deck hatchways, and that is for the localising of an outbreak of fire. 


In recent years, fire and its prevention on board ships has been occupying the attention of many 
minds and the writer thinks that it is not generally known how many fires do occur annually on ships at 
sea or in port. Dr. Montgomerie ina paper on “Safety at Sea” which he gave at the International Meeting 
of Naval Architects and Marine Engineers in New York this year, gives a very comprehensive analysis of 
fires reported for a twelve months period, from March 1930 to February 1931. 


The table shows that for that period a total of 688 cases of fire were reported; many of them, no 
doubt, would be of a minor nature and easily extinguished. Other extracts from the table which 
might be of interest to this section of the paper are that the seat of the fire in 136 cases was in the holds, 
in 96 cases in the bunkers and in 73 cases in the machinery spaces, also that 388 fires occurred in cargo 
vessels and passenger liners and 232 were on vessels between 3,000 and 7,000 tons gross. Under the 
heading “How extinguished” it shows that 139 sunk or became (. T. L. ; there is no indication of how 
many of this latter number are included the in three previously mentioned categories, probably most. of 
them were small craft and it is fair to assume that quite a number were raised again and recommissioned. 
Nevertheless the figures given are of sufficient importance to merit consideration from the steel watertight 
hatch cover aspect. 


The writer has been informed that the first indication of a fire taking place on a cargo vessel at sea 
is the smell of burning, secondly the emission of smoke from the uptake ventilators. The downcast 
ventilators are then reversed to the wind in order to stop the supply of air on which every fire thrives, 
and if the ship is not equipped with special fire extingnishing apparatus, the tarpaulins and wood covers, 
if not already burnt, are removed and water from hoses applied. 


It appears reasonable to assume that if steel watertight covers were fitted to the hatchways 
by removing the ventilator cowls and plugging the coamings, the fire in all probability would smother 
itself. The foregoing is, of course, only conjecture as the writer has never heard of any fire having taken 
place in a ship fitted with steel watertight hatch covers: experience in this direction is therefore lacking, 
The number of vessels fitted with steel covers in the ‘tween decks probably does not reach double figures, 
but there are many with them fitted on the weather deck. One can only conclude that the absence of 
fire reports from these ships isa recommendation for the adoption of steel covers. 


19 


The diagram shown here is also taken from Dr. Montgomerie’s paper and illustrates one of his cases 
of a fire originat‘ng in the engine room, and spreading forward and aft through the shelter ‘tween decks 
and from that space attacking the holds. Such uninterrupted progress of destruction in a modern ship 
scarcely seems possible. It is very probable that if steel covers had been fitted in the ‘tween deck 
hatchways damage to the cargo in the holds would have been prevented, and if fitted on the shelter deck 
the fire could possibly have been localised and extinguished before much damage at all had been done. 


+e Tt might also be mentioned that chemical and gaseous methods of fire extinguishing are conside rably 
impaired in their efficiency when wooden covers are fitted, as should these become involved there is an 
additional supply of air to support combustion. With steel hatch covers, such a contingency would be 
much less probable, if not altogether impossible. 


FIRE ORIGINATING IN ENGINE Room spreaps Forwarp and AFr THROUGH SHELTER TWEEN Decks 
AND ATTACKS HoLps. 


New Types anpD ARRANGEMENTS IN HatrcHway CONSTRUCTION. 


An arrangement which is hecoming more and more popular especially in new ship construction, and 
in itself not a patent, is the recessed hatch side coaming (see Figs. 7 to 11). The rules require that 
coamings 24 ins. in height shall be stiffened not lower than 10 ins. from the upper edge with a fore and 
aft horizontal bulb angle ; advantage is taken of this stiffener and the coaming plate is stopped short at 
its heel; the rule height of the coaming is then made up by the fitting of another bulb angle standing 
vertically on the horizonal one with its heel some 4 or 5 ins. from the coaming plate. The ledge thus 
formed provides an excellent support for the web beams and eliminates that objectionable projection of 
the hatch web shoes into the hatchway. As both the upper and lower mounting angles can extend to the 
extreme end of the web its depth here can be less than half its middle depth (as required by Lloyd’s Register) ; 
the doublings for flushing up the ends can also be omitted. It will be seen that the stiffening afforded 
to the coamings by the web slide angles is now lost, also that the load on the cover and webs is taken at 
the top of the coaming plate instead of in the slide angles at the bottom, therefore, a slight increase in 
the thickness of these plates is necessary, or vertical stiffening may be fitted on the outside of the 
hatchway. 


As the webs must necessarily house at the same position each time to suit the length of the wood 
covers, snugs or other devices are fitted for that purpose. The arrangement lends itself to the rapid 
opening and closing of the hatchways and various patents are in force for the transport of the webs by 
rollers to the end of the hatchway. 


Battening cleats are usually of cast steel or mild steel stampings and are riveted to the coaming 
plates. Since the fitting of horizontal bulb angle stiffeners has been compulsory on most coamings, this 
she!f has been found to be a suitable place for the fitting of cleats; such cleats, however, are of a different 
type from that contemplated in the rules and are in fact, plain angle iron lugs; and their fitting on the 
horizontal stiffener protects the wood wedge, to a very great extent, from being washed out by the sea, 


20 


[t seems paradoxical that although the rules, under “ Security of Hatch Covers” state that ring bolts 
or other fittings for lashings are to be provided—also with regard to hatchways whose breadth is greater 
than 60 per cent of the breadth of the deck, fittings for special lashings shall be provided—yet there is no 
rule asking for the provision of lashings. 


A usual arrangement, in say a 20 ft. hatchway, is to have three ring bolts each side and a 2 in. wire 
laced through them athwartships and diagonally over the hatchway. 


In the case of the broad hatchways, Fig. 5 shows a system consisting of three separate lengths of 
wire across the covers and a further length fitted fore and aft, knotted to the cross wires and its ends 
secured to the winch or any other convenient fitting. 


The Board of Trade have issued instruction for the guidance of Surveyors regarding lashings for 
coal-carrying vessels not exceeding 300 ft. in length :— 


(a) Each section of covers should be efficiently and independently secured by flexible steel wire 
rope lashings or other equivalent means. 


(6) Where the hatch covers exceed 6 ft. in length there should be an independent wire rope 
lashing or equivalent at each section of covers, and when fitted fore and aft, each lashing should be 
placed not more than 3 ft. from the end of the cover and should be set up by a Warwick screw 
attached to the deck with as easy a lead as practicable, 


(c) When the covers are fitted athwartships they should be similarly secured with wires laid 
fore and aft; in such hatchways more than 30 ft. in length, additional cross lashings will be 
necessary. 


Fig. 6 shows an arrangement as complying with the above. 


In view of the increasing number of patentees and designers of improvements to all the component 
parts of the orthodox system of hatchway construction, and also, which is more significant, of the number 
of ships on which these new ideas are being adopted, one cannot fail to note that some shipowners are 
apprehensive that the old system of hatchway construction is a costly one in its operation or that its 
security stands in need of improvement. 


As regards the expense in adopting the new ideas, some are comparatively cheap while others are more 
costly ; most of the improvements can be fitted to existing ships and some can be fitted piecemeal as the 
ship comes into port. With the complete steel cover arrangenent which does not require tarpaulins, 
the cost, including royalties, is an item which has to be investigated for comparison with the running 
expenses of renewals and repairs to wood covers, tarpaulins, battens, wedges and lashings. In the 
building of a large ship the difference may not be of any great moment, but in small tramps it may 
require some consideration. Some small coasters are now fitted with steel watertight hatch covers, and 
it 18 understood that the extra expense has already been justified by the facility and expedition in opening 
and closing the hatchway. In a line of large passenger and cargo ships, the superintendent has informed 
the writer that in his company’s ships which have been fitted with watertight steel covers a saving 
exceeding £200 per annum per ship has been shown. 


In the following pages a description is given of the various improvements to hatchways which have 
come to the writer’s notice. 


HarcHway BrAms. 


Fig. 7 shows a patent combination of recessed coaming and hatch web t ransporting system. In the 
illustration the web is lifted and ready for the rolling gear to transport it to the end of the hatchway ; if 
it is desired to remove the webs entirely from the hatchway, the derrick can be set to plumb one position 
and the webs brought to that position. The patentee claims rapidity in the opening and closing of 
hatchways by the elimination of the use of derricks in moving the web beams, these being easily rolled 
hy one man at each end of the web to the end of the hatchway, also, during loading and discharging, to 
the absence of web beams lying about the deck and so hindering the work. 


21 


The rolling gear (Fig. 8) is, of course, portable and can be used for any of the webs. It is nie on 
the bulb of the vertical bulb angle coaming with the lever vertical, two clips fasten on to the flanges of 
the upper mounting angles of the web and by pulling the lever down until a small wheel on the handle 
also rests on the coaming, the web beam is thereby raised about 14 ins. to clear the snugs on the 
inside of the coaming, and at the same time its weight is moved sufficiently far back in the direction of 


the handle so that the handle is kept firmly down on the bulb. 


To drop the web into position, the lever of the rolling gear is raised and the web ends fall down 
between the positioning snugs, the safety lock is then turned round and the web is prevented from being 
accidentally lifted. Small triangular pieces of steel are welded into position at the heel of the vertical 
bulb angle; this ensures that the web, should the upper edge of the bulb angle coaming get knocked out 
of alignment by cargo, will always centre itself in the hatchway. 


Figs. 9 and LO show another arrangement of the recessed hatch coaming and roller beam. ‘The beam 
is raised a few inches by a lever which has its fulerum on the top of the bulb angle coaming ; a roller 
carriage is then slipped in under each end of the beam and the beam, provided the hatchway is of 
pare allel breadth, can be rolled to either end of the hatchw ay. In this case the roller carriage is kept on 
its track by the coaming plate projecting about one inch above the heel of the horizontal bulb angle 
stiffener. ‘To ensure the correct spacing of the beams when the hatchway is closed, the projection of the 
coaming plate is recessed back to the level of the horizontal B.A. stiffener. A slip bolt is fitted at the 
end of the beam which engages in a hole in the coaming and prevents the accidental lifting of the beam. 


The patentee claims safer housing for the hatch beams; actual shipping space in the square of the 
hatch clear of obstructions; upkeep costs reduced; deck space not hampered by beams lying around and 
the ability, in opening the hatchways, to move the beams without the use of steam. 


Fig. 11 shows a similar arrangement of recessed coaming and sliding beam. In this case the beam 
does not require to be lifted prior to rolling as it rests permanently on a pair of rollers which are fitted 
to the web ends and which run on a track on the coaming ledge; a locking plate fitted between the upper 
mounting angles engages in slots in a strip of steel w hich is welded to the vertical bulb angle and so 

regulates the position of the webs for wood covers. When the webs are housed at the end of the hatch- 
way this strip also prevents the accidental lifting of the webs. A rope lanyard through a hole in the end 
of the web is used for drawing it into the desired position. 


The patentee claims a substantial saving of time, as from 8 to 9 per cent of stevedore’s time is used 
in the uncovering and covering of hatchways at the commencement and completion of each day’s work ; 
deck space for unshipped beams is no longer necessary; damage by swinging beams to wood decks, steam 
pipes and casings is eliminated and the hatchway opening is increased some 8 or 9 inches because the 
beam sockets or slide angles, which also damage the cargo, are dispensed with. 


The three foregoing systems can also be adopted at all ‘tween deck hatchways, the 9 inch bulb angle 
coaming on these decks being fitted some 4 or 5 inches back from the opening and the deck plating 
forming the track or ledge for the beams. Wood covers and tarpaulins are, of course, necessary on the 
weather decks, 


Woop AND STEEL HarcH Covers. 


Figs. 12 and 13, A, B and C, show a very simple and easily effected improvement to wood hatch 
covers. It consists of the fitting of mild steel open bands or closed end shoes to the ends of the single or 
double plank covers. No constr uctional alteration of any kind is required ; the bands or shoes are supplied 
by the patentee and the carpenter can fit them during the voyage or they can be fitted piecemeal as the 
ship comes into port, one hatchway or part of one at atime. Their weight is not excessive ; for the open 
bands, ranging from 1}? lbs. for the 9 inch cover to 34 Ibs. for a 22 inch one; for the closed end shoes, 
about a quarter of a pound more. 


It is claimed and it appears obvious, that these fitments will prevent warping, splitting, rotting and 
rounding of the hatch ends and that they will keep a full and permanent fit on the hatch rest bars; 
something like a quarter of a million have already been supplied to ships. 


2? 


A further improvement, which the patentee offers with double plank covers, is the fitting of a 
galvanised centre vertical plate between the planks; the weight of this plate is less than 1 Ib. per foot and 
can be fitted on covers which either have open bands or the closed end shoes. The strength of this 
combination is of course, much in excess of the regulation cover, being about 60 per cent stronger. 


Keonomy, no doubt, has been the governing feature in the adoption of these end fittings but it is 
recognised that this is a very good first step towards producing greater safety of the hatchways. 


A system of hatch covering which does not require any alteration, only some little addition to the 
existing construction, is shown in Figs. 14 and 15. The invention incorporates the use of a uniform 
rolled length of 0.G. or wedge-shaped steel section, riveted or welded to the hatch coaming or to the 
extension plate on the alternate hatch webs : they are fitted just above the rest bars so that a suitable 
recess is formed for the ends of the covers to be secured. The O.G. section is slotted out at intervals, 
either in way of one end of the cover or at both ends, the slots being long enough to suit the width of 
the cover ; the covers are placed in the slots and slid along the rest bars into position, the final or 
locking cover which is made of oak is half the width of the other covers. The covers are chisel-shaped 
or champhered at the upper edges of their ends to suit the angle of the recess, and fitted with substantial 
galvanised iron shods to protect and keep them in shape and enable them to slide easily into place. The 
locking plank has at each end, in the case where the O.G. section is slotted at each end of the plank, 
a specially designed turnbuckle ; when the special sections are slotted at one end, only one turnbuckle 
is required. The turnbuckle ring acts as a hand grip for lifting out the plank and also for turning it 
into position, the ring then falls into the recess and the turnbuckle cannot turn loose. The illustration 
shows that if required a locking device can be fitted so as to lock the turnbuckle in position with a key ; 
this arrangement is suitable for hatch ways over store-rooms or in general to prevent pilferage of the cargo. 


The patentee claims that the covers cannot be washed out nor be dislodged, also that as the covers 
are secured below the tarpaulins, lashings and locking bars which seriously damage the tarpaulins can be 
dispensed with. 


There are several designs (two of which are here described) of steel hatch covers which are similar 
in length, width and thickness to the ordinary wood covers, and can replace the latter if an owner so 
desires without any structural alteration being necessary. The usual supporting web beams, tarpaulins 
and battening arrangements, of course, are required. 


Fig. 16 shows a general lay-out of a hatchway with four arrangements of this particular type of cover. 
(A) The short and broad covers or the long and narrow ones, which simply replace the wood covers 
without any structural alterations or additions. (B) These covers are strong enough to dispense with 
the intermediate hatch beam ; e.g., in a 30 ft. hatchway only two instead of five hatch beams would be 
required. In an existing ship the remaining supporting beams would require reinforcing in accordance 
with the increased spacing. (C) Examples of long and broad covers also strong enough to dispense with 
the intermediate beam, but their weight would necessitate their being lifted by the winch. The covers 
are made of mild steel plate } in. or ye in. in thickness, 24 ins. to 6 ins. deep, with a lower flange and cross 
stiffeners as necessary, the fastenings being made by welding. The covers have been subjected to B.'T. 
tests and found to be 60 per cent stronger than wood covers. They are, no doubt, a considerable 
improvement to the wood, and the patentee states that in a particular ship which requires the wood 
covers renewed every 18 to 24 months, these steel covers have been fitted for now 34 years and no 
sign of wear nor tear yet visible. Fig. 17 shows the comparison between this type and the wood covers, 
the broad covers being the wood ones. The photograph gives a pretty good idea as to what state of 
dilapidation wood covers reach, and it is by no means exaggerated. 

Figs. 18 and 19 is another arrangement of small section steel covers which replace the wood ones. 
These are made of mild steel, each plate being flanged at the sides and ends, and the surface perfectly 
flat. The covers can be made of such size as to be readily man-handled, or they may be made of a 
larger size if it is desired to move them by the ship’s winches and derricks. 

The design can also incorporate a locking device for the covers which are then made, for about 
2 ins. at each end, stepped or dished for a depth of $ in. Between each row of covers running the 
width of the hatchway are placed two tee-bars, one for each half-width of the hatchway. Plate wedges 
on the vertical flanges of these tee-bars engage with corresponding wedges welded on the hatchway beams. 
while the horizontal flanges overlap the stepped ends of the covers. 


28 


In the centre, and running the full length of the hatchway, is an adjustable locking expander ; 
the turning of a handle at either end of the hatchway varies the width of the expander a matter of 
3 or 4 ins.; this act of expansion locks the covers, tee-hars and expander to the hatchway beams. 

One of the vessels, which has been fitted with these covers, has already had a“ heavy weather ” test 
and the master in a letter to his owners states that judging by the wholesale damage to rails and deck 
fittings by the extraordinary violence of the seas, if ordinary Wood covers had been fitted to the No. 1 
hatchway the covers would surely have been stove in. 

Slab covers is a type of hatch covering which has been in vogue for many years and of which there 
are several designs and patents. 

In principle it consists of a number of ordinary wood hatch cover planks of the required thickness, 
held together by an angle frame or simply by a number of cross angle bars. The size of each slab is 
generally the half width of the hatchway by the spacing of the web beams. 

Fig. 20 shows the frame arrangement which is a rectangle of angle iron strengthened with cross 
ties and corner plate brackets ; the wood planks are placed within the frame and bolted to it. By this 
arrangement deterioration and rounding off of the plank ends is prevented as the frame itself rests on 
the rest bars in the hatchways. 

The second arrangement with the tranverse angle bars, bolted to and under the wood covers is 
shown in Fig. 21. The angle bars are hinged at their mid length thus permitting the slabs to fold up 
double and so enable them to stow more easily. 

In a third type, Fig. 22, the wood planks form the slab by being held together with cross angle 
bars, which hang inside the hatchway, the ends of the planks in this case rest on the rest bar. 

One or more ring bolts are fitted in the slabs for their removal by the derricks ; tarpaulins and the 
usual battening gear have always to he used with the slab type of cover, 

Figs, 23 and 24 show a type of slab steel hatch cover; like the wood slab cover its size is half the 
width of the hatchway and is strong enough, in a fore and aft direction, to eliminate the intermediate 
hatch web beam. The ship’s derricks lift and stow the covers on the deck : tarpaulins and the usual 
hattening down gear are required. 

If desired the covers can be made to hinge at the side coamings, they fold over and rest on the 
bulwarks and so provide a working platform for loading or discharging, A patent hinge is incorporated 
in the half round at the top of the coaming and is so designed that there is no obstruction to the 
hattening down of the tarpaulin. So far the hinge cover has only been fitted to the smaller sizes of 
hatchways, as shown in Fig. 24. 

The object of the design is the elimination of wood covers, and although tarpaulins must be used, if 
they do become ripped or torn, water in great quantities cannot enter the hatchway as these steel covers 
cannot be washed off nor displaced. 


Figs. 25 to 28 show types, by the same patentee, of steel hatch covers which are weathertight in 
themselves and do not require tarpaulins nor battening gear, The first cover of this design was fitted 
in 1928 and an increasing number are being fitted each year. 

The covers are constructed of steel plates with channel or bulb angle frames and suitable stiffeners. 
They are arranged to roll out horizontally to sides for use as cargo platforms or to roll out and pivot 
vertically to one end or both ends of hatchways, the sections being of such size to afford ease of moye- 
ment and rapid stowage. The covers may be in one or more sections ; each section is mounted on four wheels 
and each wheel has an eccentric bush. A man with a marlin-spike gives a half turn to each bush which 
action raises the section from its watertight seating and the section is ready to be rolled off. To secure 
the covers in the closed position, after they have been lowered on to the packing, patent wedge-headed 
cleats which pass through slots in the bulb angle stiffener on the coaming engage in lugs which are attached 
to the side plates of the covers; the cleats are then locked into position with tapered pins (see Fig. 29). 

The patentee claims that each section can be opened or closed by two men in two or three minutes, that 
by unfastening the cleats and raising the covers extra ventilation can be obtained and still remain rainproof, 
that when steel covers are also fitted in the tween decks fires can be localised. that experience has proved 
that there is no upkeep and renewal costs, there being no lashings, tarpaulins, battening bars nor wedges 
nor any web beams. 


24 


When two or more sections are fitted on one hatchway the edges are made watertight with hemp 
packing and held tight with toggles spaced about 3 ft. apart. 

Fig. 25 shows a two section cover closed and Fig. 26 a three section cover in the Open position ; in 
the later case the middle section is first rolled on to an end section and then both sections rolled to the 
end and tipped up together into the stowed position. Fig. 27 shows a long hatchway with all the cover 
sections rolled to one end and stowed there. Fig. 28 shows the arrangement when the covers are rolled 
to the sides and form cargo platforms. : 


Fig. 30 shows a type of steel cover which has been fitted on quite a number of ships, the first being 
so equipped over 20 years ago. These covers were mostly fitted to the hatchways of ore-carriers and self- 
trimming colliers but they seem to have gone out of favour these last five or six years, possibly on account 
of their great weight. Special gear and erections had to be constructed for opening them and for keeping 
them open and consequently a head of steam had always to be maintained for the winches to operate them. 
They, however, served the primary purpose of producing a very seaworthy ship but apparently their un- 
wieldiness retarded their greater adoption. In the latest ships to be fitted with this type, the covers were 
in halves, thus facilitating their opening and closing. 

The construction of the covers was quite novel, the undulating form of the top plating eliminated 
the necessity of having transverse stiffeners and so made them lighter than they would have been with 
flat plating. Watertightness is maintained by a strip of greasy hemp packing which is fastened into and 
protruding slightly from the sides of the covers, the whole resting on the bulb angle stiffener on the 
coaming and being screwed up tightly to it with toggles, spaced about 3 ft. apart; the holes in the hinges 
are oval to permit of this operation. 

Fig. 31 shows the arrangement of the greasy hemp watertight packing at the coamings and at the 
joints. 

Owing to the sail area which the covers present when opened it has been known on occasions for a 
moderate gale of wind to break the vessel’s moorings: precautions are therefore taken to run out extr: 
wires when loading or discharging. 


A hinged steel cover which has been fitted to the hatchways in a number of large passenger and 
cargo ships is shown in Figs, 32 and 34. The cover is constructed of steel plates and stiffened with 
channel bars ;_its weight is supported by the ends of the channels resting on tee bar brackets fitted on 
the inside of the end coamings ; the sides and ends of the cover are about 5 ins. deep and stiffened with 
an angle bar. The complete cover is made somewhat larger than the hatchway opening and encloses 
the coaming top ; a canvas packing is laid on the flange of the horizontal bulb angle coaming stiffener, 
and hy clamping the flange of the angle bar on the cover side to it, a perfect watertight joint is made. 
The web beam, which is seen in the photograph, is from a hatchway below. 

The clamps, shown in Fig. 33, are spaced about 3 ft. 6 ins. apart ; they are quit? loose, and to 
prevent them being lost, they are held by an eye bolt to the underside of ‘the horizontal stiffener. 
Hinges of good solid construction are fitted at one end of the hatchway, and the winches are used for 
the opening and closing of the covers. 

The type is very suitable for hatchways up to about 24x 16 ft.; larger sizes require two covers for 
easy manipulation. 

To ascertain the respective times in opening two hatchways with different coverings, a test was 
made on board one of the ships ; with the tarpaulin and wood cover arrangement it took ten men fifteen 
minutes to perform the work, whilst three men opened up the hinged cover in tive minutes ; the latter 
performance was done with considerable less noise than the former, which is a very desirable feature in 
passenger ships. 


Figs. 35, 36 and 37 show a watertight steel hatch cover which has been fitted on several ships recently. 
The cover is in sections, the number depending on the number of hatch webs which it is intended to he 
fitted in the hatchway ; each section rests on the web and on the rest bar or Tyzack section just within 
the top of the coaming. In smaller hatchways the covers can lie fore and aft and so dispense with the 
web beams. 


The joints of the covers are made watertight by long channel bars, tilled with jointing material, 
which lie upon the abutting edges of the covers and are secured thereto by toggles. The bars run the 
full width of the covers and project over the shutters, to which they are also bolted. 


There are four shutters, one hinged to each side and end of the hatch coaming. They are of channe! 
section, containing two lines of jointing material separated by hard wood. One line of jointing bears 
against the outside of the couming, and the upper line bears against the angle iron edge of the covers 
which project above the coaming when in position. When released, the shutters hang down against the 
coaming. 


The connections of the various parts of the covers is effected by welding, and this arrangement 
keeps the weight down to a minimum, On a hatchway 28 ft. 6 ins. by 18 ft. where four covers are 
fitted resting on transverse beams, the excess weight per hatch is about 3 tons. When the size of the 
cover is ine reased, and the number of beams reduced, or when the beams are incorporated in the covers 
by strengthening the scantlings, then this figure becomes much smaller. 


The Board of 'Trade carried out tests on one of these covers, 18 ft. by 7 ft. 6 ins., by loading it with 
weights totalling 40 tons, which is equal to a load of 10 ft. 6 ins. of water. The maximum deflection of 
the cover was one-half inch, and when the load was remoyed no deflection could be measured. The 
Sana states that this indicates the virtue of the welded construction and the soundness of the design ; 

s also claims that the cover is as strong as the surrounding deck plating and is perfectly watertight, 
ee the jointing material retains all its original efficiency in all climates and when submerged in water, 
and only” requires occasional coating with liquid tallow. 


Figs. 38 and 39 show an arrangement of the hinged steel watertight cover. In this case there are 
four sections, the end sections are hinged to the end coaming stiffener and the centre sections are hinged 
to the end sections. The modus operandi is to unfasten the toggles at the middle watertight joint and 
uso all around the coaming: a wire from a derrick is then fixed to the inner edge of the centre section 
which hinges over on to the end section, the wire is then fixed to the inner edge of the end section and 
both are opened up and stow in astanding position at the ends of the hatchway, as shown in the photogr aph. 


Any size of hatchway can be fitted in different ways, viz. :—Small hatchways, one cover hinged in two 
sections and folded to one end of the hatchway: hatchways about 24 to 30 ft. in length, one cover but 
hinged in three sections and folded to one end of the hatchway : above 30 ft. in length, two covers, each 
in two sections and folded to each end coaming: in the latter case the cargo winches must be placed on 
deckhouses or platforms so that the winchman can haye a clear view. 


Special patent packing is used for effecting watertightness; along the hinges by the weight of the 
covers themselves and at the coamings and middle joint by bolts or toggles. 


The patentee claims simplicity and rapidity in opening and closing the hatchways, saving in time 
and upkeep, more safety at sea and elimination of hatch webs, wood covers, tarpaulins, wedges, hattening 
hars and lashings. 


Fig. 40 shows another type of steel watertight hatch cover. It comprises a number of sections, 
dependent on the length of the hatchway: each section being 7 to 8} ft. long. Two rollers, using the 
horizontal bulb angle on the coaming side as a track, with eccentric spindles, are fitted at each side of 
each section and by giving the spindle a half turn the cover is raised slightly from its bearing on the 
bulb angle ; each section is then rolled to beyond the end of the hatchway and stowed in a vertical position, 


A suitable pin projecting from the side of each section engages in a rest at the stowing location and 
a wire from the winch draws the section up into position. 


The watertight arrangement at the joints and at the coaming is shown in Figs. 41 and 42, A strip 
of resilient rubber packing is fitted on one edge of each section and by a system of serew jac ks operating 
at each corner of the hatchway the rubber is compressed and draw bolts hold the nectines together. Ti 
will be seen that the rubber fitted in the sides of the covers above the coaming top does not take the 
weight of the cover but is only compressed sufficiently to effect watertightness; the weight is taken by 
the side plating of the cover with its edge resting on the bulb angle stiffener. 


26 
Cleats for holding the cover down, although it is reckoned that its weight is sufficient for this, are 
fitted through the bulb angle stiffener; they are hammer-headed in shape and by unscrewing the cap nut 
underneath, the cleat can lie fore and aft on the bulb angle when the cover is being opened. 
Another arrangement by the same patentee has the cover in two sections with the joint at the centre 
line. In this case the section rolls out sidewards on a small half round section welded to the deck, the 
rollers being fitted at the foot of the legs attached to the coyers. 


The latest type of steel watertight hatch cover is shown in Figs. 43 and 44. The cover consists of 
a number of sections placed athwartships across the hatchway. The half width of each section. is 
approximately equal to the height of the coaming. 

A small axle pivot is fitted at each end of each cover section on which the roller Jack fits, the cover 
is then raised about 2 ins. and clamped in position, rolled to beyond the hatchway end, unclamped, 
tilted and lowered on to bulb plate supports. 

In this way the covers are operated by hand, the fore and aft bulb angle stiffener on the coaming 
forming a track for the rolling jacks to transport the covers to the end of the hatchway. 

Welding is employed throughout for the connections of the plates and angles of the covers. 

At the joints of the sections and at the edges above the coaming tops, watertizhtness is secured by 
strips of special rubber permanently fastened to the covers and all the joints held tightly togethea by 
special malleable cast-iron captive wedges. 

The patentee claims a perfectly clear hatchway opening, simplicity and rapidity in moving the 
covers, and economy in time, labour and materials, as compared with the ordinary type of covering. 

One section of the cover has been tested with a load corresponding to a 7 ft. head of water, the 
deflection noted disappearing entirely when the load was removed. Fig. 444 shows the cover during test. 


BaTrENING ARRANGEMENTS. 

Figs. 45 and 46 show a mechanical method of battening down the tarpaulins ; it is applicable to 
coamings with or without horizontal bulb angle stiffeners. The arrangement eliminates the use of wood 
wedges, and therefore has much to be said for its adoption. 

It consists of a special type zed-shaped cleat, is movable in its base, which is riveted at the 
regulation spacing either to coaming direct or to the horizontal stiffener ; its upper end is also free to 
move in clips on the battening iron ; the latter only takes three or four of the cleats, and at its end it is 
connected to the adjacent battening iron by a Warwick screw ; by turning the screw the irons are drawn 
together, and in so doing the cleats press the battening irons and’ the tarpaulins against the coaming and 
so effect a watertight joint. The patentee states that such an arrangement has been tested by its being 
submerged for six days, and no leakage of any kind occurred. 

A later device by the same patentee is shown in Fig. 47. Here the ordinary battening iron is used, 
hut each cleat works independently. The cleat is free to revolve on a pin, which is screwed fast in the 
horizontal bulb angle coaming stiffener; it has a wood facing and is swung round to bear on the 
battening iron, working something like a wedge; it gets a few blows with a hammer and is then locked 
in position with a special spanner. 


In conclusion, the author hopes that his effort in describing the orthodox method of hatchway 
construction, with all its possible and probable deficiencies. and his contention that ship owners should 
be induced to improve this vulnerable part of the ship, has been sufficient to create a discussion which. 
after all, is the main object of the paper. The subject is virginal and topical, and should appeal to 
most members of this Association as it embraces the safety of ships and the safety of those who go 
down to the sea in them. 


The author wishes to thank those gentlemen and firms who, by their generous assistance in 
supplying information and photographs, have helped to make this part of the paper interesting. 


APPENDIX I. 
Abbreviated Reports of Board of Trade Official Inquiries. 


A. Lost with all hands in heavy weather during a voyage from Liverpool to Penryn with a cargo 
of maize in bulk. 

This was a small coaster with a raised quarter deck and a forecastle and one long hatchway. Her 
one hold was partly filled with maize in bulk, then some 60 bags were filled and laid on top but there 
still remained space for about five more tons of grain. 

The vessel sailed and was never again heard of, the only evidence available was the experience of 
another vessel which left Liverpool at the same time and encountered very heavy weather. 

The finding of the Court was :—I have come to the conclusion that at the height of the storm she 
pitched and rolled so heavily as to cause the cargo to shift and give her a list and that, whilst lying in 
this position, she shipped heavy seas on hoard which burst in the hatches, causing her to fill rapidly and 
founder, taking all hands and everything down with her. 


B. Foundered in the North Sea, during heavy weather, whilst on a voyage from Hull to Calais with 
a cargo of creosote in barrels in the hold and on the deck. 

This was a 135 ft. iron screw steamer of 209 gross tons of the raised quarter deck type with two 
main hatches. Owing to bad weather and an increasing list to starboard the vessel came fo anchor and 
part of the deck cargo was jettisoned; the tarpaulins were then found to be chafed through at the 
coamings ; another cover was fitted on the main hatch but the fore hatch could not be attended to as 
water was then coming over the coamings; the weather getting worse the master decided to run for 
shelter and whilst doing so a tank of paraffin in the stokehold burst and caused a fire, the engineers 
stopped the engines and came on deck, the ship immediately became unmanageable and lay in the trough 
of the sea, the list increased and water entered the holds in larger quantities and the ship capsized. The 
master, his wife and two young sons and eight other hands were on board : only one was saved. 

The finding of the Court was :—That the cause of the loss of the ship was primarily due to the 
engines being stopped on account of fire in the stokehold, the ship losing way and becoming unmanage- 
able and secondly, owing to heavy weather the ship listed, the deck cargo damaged the hatch tarpaulins 
and the seas entered the hold in such quantities as to cause her to capsize. 


GC, Abandoned and lost in the North Atlantic Ocean during heavy weather whilst on a voyage 
from New York to Cherbourg with a cargo of grain, in bulk. 

This was a 400 ft. two deck cargo steamer built in 1918; she had seven water-tight bulkheads, 
four main cargo hatchways and bunker hatchways on the bridge deck. 

Owing to a steering chain breaking, the engines were stopped to repair same, during which the vessel 
lay in the trough of the sea, the cargo shifted and the ship took a list of about 25 degrees to port : when 
the engines were started she would not come up to the wind, the list increased and seas breaking over her, 
water entered the stokehold and engine room through the bunkers, the tarpaulins of the port bunker 
hatch on the bridge deck having been torn and washed off hy the heavy seas. ‘The accumulation of 
water in the stokehold which had entered by the bunker hatch extinguished the tires of the port and 
centre boilers and could not he dealt with by the pumps. When the list had increased to about 
40 degrees the ship was abandoned, the water then being up to the main hatches. 

The finding of the Court was :—That the primary cause of the loss was the parting of the starboard 
wheel chain and the consequent list which rendered the ship unmanageable. 


D. Destroyed by fire in the River Thames whilst on a yoyage with a cargo of petroleum spirit in 
steel barrels stowed in the hold and on deck. 


This was a wood sailing ship of 66 tons gross, with two hatchways, wood fore and afters, wood 
covers and tarpaulins, 

The master was last seen sitting on the forward hatchway which had the tarpaulins turned back for 
ventilation ; the wood covers were known not to fit closely but left openings between them sufficiently 
large to admit one’s fingers ; the master was a heavy smoker and, in the absence of direct evidence, it is 
presumed he inadvertantly dropped a lit match into the hold, causing an explosion and setting the vessel 
alight. The master’s body was afterwards found, his tobacco pouch in his pocket but not his pipe nor 
matches. 

The finding of the Court was :—That the loss was caused by explosion and fire resulting from a 
naked light igniting petroleum vapour, but there is no evidence as to what that light was. 


E. foundered in the North Sea during heavy weather whilst on a voyage from Blyth to Rotterdam 
with a cargo of coal. 

This was a 290 ft. self-trimming collier with a raised quarter deck, poop, bridge and forecastle ; she 
had four large hatchways, the two forward ones occupying 52 per cent of the forward well deck and the 
two after ones 46 per cent of the raised quarter deck. The hatch coamings were 48 and 42 ins. high, 
the usual cleats, battens and wedges were fitted, two tarpaulins to each hatchway but no locking bars. 

The vessel encountered heavy weather and when it was found that the upper tarpaulin of No. 2 
hatchway had been split and torn, she was turned round, speed reduced and a new tarpaulin fitted, a 
zig-zag cross lashing of 3 in. manilla rope being used as an additional protection. Bad weather continued 
and a heavy sea split both tarpaulins of No. 2 hatchway and washed them off by the cleats, wood covers 
were also washed away and attempts to fit new planks and re-batten the tarpaulins failing, water continued 
to pour into No. 2 hold and when the ship had a heavy list to port and was down by the head the crew 
abandoned her. : 

The finding of the Court was :—That the loss of the vessel was due to the tarpaulins covering No. 2 
hatchway—although in good condition—being defective in strength to withstand the great strain to 
which they were subjected by heavy seas breaking on to the abnormally large area of hatchway which 
the tarpaulins covered; and consequently the seas flowing through the hatchway into No. 2 hold in 
quantities with which the pumps could not cope. 


F. Presumably foundered with all hands off the Yorkshire Coast whilst on a voyage from Hartlepool 
to London with a cargo of coal. 

This was a 230°ft. self-trimming collier with a raised quarter deck, short bridge, long well deck 
and a forecastle ; she had four large hatchways, the forward two occupying 47 per cent of the area of 
the forward well deck and the after two oceupying 35 per cent of the area of the raised quarter deck, 
Each hatchway had five pitch pine wood fore and afters and the wood covers were white pine single 
planks 9 by 3; the usual battening arrangements, no locking bars, but 24 in. rope zig-zag lashings 
were fitted. 

The vessel left Hartlepool and nothing was ever seen or heard of her since. Depositions from 
the masters of eight other vessels which were off the Yorkshire Coast about the time in question, all 
testified to the exceptional severity of the N.N.W. to northerly gale which prevailed in that vicinity then. 
The master of one of the vessels had a log entry which read “ Vessel shipped tremendous seas that filled 
her fore and aft, and tearing tarpaulins.” 

The Court considered that a more effective method of securing the tarpaulins than by rope lashings 
would be by wood or iron fore-and-afters, well secured at their ends, which would prevent tarpaulins 
splitting and tearing. 

The finding of the Court was :—That the loss of the vessel, with all hands, was probably due to 
heavy seas breaking in the covers or tarpaulins over the large No. 2 hatchway, and that a contributing 
cause was the possible shifting of untrimmed cargo; but. in the absence of direct evidence. the Court is 
unable to determine the exact cause of the casualty. 


dy 


=< 


G.  Foundered in a storm when on a voyage from Melbourne to Manila with a cargo of coal. 

‘This was a wood sailing vessel of 901 tons gross, built in 1877, in the U.S.A. 

After battling with a storm for about two days the main hatchway was stove in and water gained 
rapidly in the hold; the vessel was abandoned, but, out of a crew of 14 and the master’s wife, only four 
survivors reached the Philippines after being 23 days in an open boat under very trying conditions as to 
food, water and exposure. 


The finding of the Court was :—That the casualty was due to overwhelming stress of weather, 
under which the vessel was greatly damaged and filled gradually beyond the power of the crew to pump 
out, the consequent straining and irreparable damage to the hatches, foundering became inevitable. 


H. Lost, with all hands, whilst on a voyage from London to Italian ports with a cargo of sugar in 
bags. 

This was a 300 ft. spar deck ship of 2,034 gross tons, built in 1892. She had three decks and a 
promenade deck amidships and four hatchways and was built for the carriage of passengers and cargo: on 
this trip no passengers were on board but sugar in bags was stowed in the 2nd class saloon. 

The vessel had been laid up for some considerable time and sailed without complying with its 
classification society’s requirements and so at the time of the disaster was not in class. There is no 
positive evidence that the vessel was in an actually unseaworthy condition although there is evidence 
that the boilers were in a defective condition, and the Court considered that the bath and soil pipe 
openings in the ship’s side which were below the load water line, would be a source of danger to the ship 
in bad weather. As no repairs had been effected for some time it is also probable that the hatchway 
coverings were not in an efficient condition. 

There were no survivors from the vessel, so the actual cause of her disappearance could only be a 
matter of conjecture, but in view of the heavy weather prevailing at the time, and the dangerous sea 
which was running, the Court is of opinion that she was overwhelmed by the sea. 

The finding of the Court was :—That the vessel went down and was lost with all on board in heavy 
weather, but that there is no evidence as to the actual cause of her loss. 

Though there is no evidence that as regards her hull and machinery the ship was unseaworthy, in 
view of the proposed yoyage, the Court found that when the ship sailed she was an unsafe ship for the 
following reasons :— 

(1) Wireless installation as required by law was not provided. 

(2) Her boat falls were in such a condition that the boats could not be readily launched or 
sasily handled. 

(3) She had heen so long laid up in the Thames, and such a length of time had elapsed since she 
was last thoroughly surveyed, that it was highly improper to send her to sea without first 
causing her to be dry-docked and thoroughly overhauled. 


J. Abandoned and foundered whilst on a voyage from St. Nazaire to the Mumbles with a cargo of 
pit props in the holds and on the decks. 


This was a 180 ft. steamer of 749 tons gross, built in 1920. She was of the raised quarter deck type 
with machinery aft, had two hatchways with 23 in. pine wood covers efficiently supported by webs and 
had cleats and battens for the tarpaulins. 


It appears that after the hold was filled with pit props the hatch covers were fitted in position, but 
were not covered by the tarpaulins nor secured in any way except by the weight of the pit props resting 
on them. The master unaware that his vessel was in salt water allowed the loading to proceed until the 
centre of the dise was 25 ins. helow the surface, the excess representing 28 tons overloading. 


The vessel started with a slight list but with a freshing wind and the deck cargo being not 
secured with the usual cross lashings she went over to about 10 or 12 degrees to port ; a sudden porting 
of the helm then caused her to go further over to some 30 or 35 degrees, the list being so great the 
accumulated bilge water under the boilers was clear of the strum-box and could not be pumped ont, 


30 


Water now entered the fore hatch and flowed aft, the unsecured deck cargo floated off and the vessel 
gradually settled down by the stern, the engine room then filled through the doors in the casing. ‘The 
crew took to the boats and in three-quarters of an hour the vessel sank stern first. 


The finding of the Court was :—That the loss of the vessel was due to her being overloaded to the 
extent of about 28 tons, thus giving her insufficient stability, to the partial filling of the after peak with 
fresh water, and to the accumulation of bilge water under the boiler, these quantities of water, having 
free surfaces, still further reducing her stability and ultimately causing her to take a permanent list to 
port. Under the influence of the sudden porting of her helm about 4:20 a.m. on the morning of the 
asualty, the shifting of loose water and bunker coal. and the general settling of unsecured weights to 
port, all tended to increase her already existing list. Water then found its way through the fore hatch 
into the hold, and as the unsecured deck cargo floated away the vessel trimmed more and more by the 
stern, so that water found its way aft. Finally, when the list reached about 30 degrees the engine room 
filled, thus causing the vessel to sink stern first, 


K. Left Calcutta with a cargo of eoal for Rangoon, ran into a violent cyclone in the Bay of Bengal 
and foundered with all hands. 


This was a 410 ft. cargo steamer of 5,291 tons gross, built in 1895. 


Just prior to the vessel’s departure from Calcutta the hatches had been overhauled and 12 new 
covers supplied, and the Captain had informed the Superintendent that the tarpaulins were in good order. 
The only evidence as to what happened is contained in a series of Wireless messages picked up by another 
vessel. Some hours after exchanging reports as to the severity of the storm, the “K” broadeast, * Making 
very bad weather hatches going ship so deep. Am trying to run her out of it now as last resource, 
Making water quickly in No. 4 hold if weather moderates and I pull through will you kindly stand by 
me.” Three hours later she was sending out 8.0.8. signals and although the other ship was then only 
nine miles off, having been racing towards her at 175 knots, when her position was reached nothing 
could be seen of her: the search continued till daylight but without avail. 


Another ship which was in this vicinity also reported that her hatches and tarpaulins had been blown 
away. 


The Court made special references to hatches and their construction :—From the evidence 
heard during this inquiry it is evident that the present design of hatch covers and tarpaulins is not 
considered by those most competent to judge to be proof against the seas which may be expected in 
cyclones, hurricanes, or similar violent storms. In shelter deck ships or ships with more than ten feet 
of freeboard, when fully loaded, the matter is not of such importance, but in ships like the present 
or smaller, with open main decks, the power of the hatch covers to resist large volumes and heavy weights 
of water without breaking or becoming unfastened is of vital importance to the safety of the ship. 
There is no doubt that at any rate some of the hatch covers and tarpaulins securing No. 4 hold were 
stove in or washed away, some time dpring the storm, and that large volumes of water entered the ship 
through No. 4 hateh, the ingress of which appears to have been the main contributory cause of her 
foundering. The Court feels very strongly that any ship, however small, should have a reasonable chance 
of weathering any storm in which she may be caught, whatever part of the globe she may be called 
upon to traverse. The Court feels that an investigation into an improved design of hatch cover is 
outside the scope of the present inquiry, but strongly recommends that the holding of such an investigation 
should be considered by the proper authority, with a view to introducing regulations requiring a 
stronger design of hatch cover, and method of securing them, than is at present the case in ocean-goine 
ships with open main decks whose freeboard when fully loaded is less than ten feet. 

The finding of the Court was :—As to the causes of the foundering the direct cause was the fact 
that her hatches went and she was overwhelmed by a huge sea, and this was the result. of her being 
caught in a cyclone. 


L. Lost with all hands in the North Sea, durine a voyage from the Tyne to Hamburg with a 
cargo of coal. 


te A 


31 


This was a 245 ft. self-trimming collier, of 1,533 tons gross, built in 1923: she had poop, bridge 
and forecastle and between the erections there were broad trunks on which were placed the hatchways, 
two forward of the bridge and two aft of it. The hatchways were 25 ft. 6 ins. wide or 67 per cent of 
the breadth of the ship, and the hatchway area occupied about 50 per cent of the deck area. 18 ins. by 
2} ins. white wood double plank covers were fitted with two tarpaulins to each hatchway, cleats, battens 
and wedges and rope lashings, but it is not known if the latter were in position on her last voyage. 

As there were no survivors the exact cause of her foundering could not be stated but having regard 
to the heavy seas experienced by four other vessels which were in the same Vicinity about the same time, 
it is probable that the “L°° encountered the same heavy weather. It is significant that a sister 
vessel, some eight months previously, met heavy weather when loaded and had. the tarpaulins of 
No. Land 2 split by the force of the seas and water entered the holds; it was with difficulty that she 
reached port. 

It was considered that the large areas of these openings on the weather deck of this ship (the wood 
hatches with tarpaulins), were equivalent to a loose, or portable deck, and the method of securing the same 
is of vital importance to the seaworthiness of the vessel. 

The finding of the Court was:—That the loss of the vessel with all hands. was probably due to 
heavy seas, during the gale prevailing over the S.E. section of the North Sea, breaking in the covers and 
tarpaulins of the hatchways (which were of large area), and flowing into the holds in quantities with 
which the pumps were unable to cope: but, in the absence of direct evidence. the Court is unable to 
determine the exact cause of the casualty. 


M. Lost during heavy weather whilst on a voyage from Barry to Ghent with a cargo of coal. 

This was a 280 ft. self-trimming collier, of 2,147 tons gross, built in 1924; she was single deck type 
with poop, bridge and forecastle and broad trunks between the erections ; the hatchways which were 28 ft. 
wide (67 per cent of the breadth of the ship) were situated on the trunks, two forward and two aft of the 
bridge. Covered with single plank wood covers 11 ins. by 3 ins. each had two tarpaulins and the 
regulation battening arrangements and rope lashings were supplied. 

In the early morning, when it was blowing half a gale, the ship was seen to be taking heavy seas, 
especially on No. 3 hatch, extra lashings were put on and Nos. 1 and 2 were relashed: between 8 and 
9 am. the tarpaulins of No. 3 were found to be ripped along the starboard coaming; they were 
then nailed to the wood covers: later the starboard fore corner wood cover was washed overboard, there- 
after the vessel took a list to starboard, the rope lashings held but the tarpaulins were washed over to the 
port side, more wood covers were lost and No. 3 hold filled rapidly with water. The ship was abandoned 
and the crew took to the boat. 


Another vessel in answer to the S.O.S. call arrived and the lifeboat in coming alongside 
capsized and only 2 of the crew of 20 were saved. It appears that the weather was so bad, which fact 
was corroborated by the officers of another ship which arrived, that lifeboats could not be lowered to 
attempt rescuing the men in the water, = 


Considering the large area of the hatchways, which were approximately half the area of the deck, the 
wooden hatches were equivalent toa portable deck and the method of securing them is of vital importance 
to the seaworthiness of the vessel ; also considered by the Court that a more efficient method of securing 
hatches against wind and sea, to prevent water getting below, such as “locking” or securing bars fitted 
across each tier of wooden hatch covers. 

The finding of the Court was: —That the loss of the vessel was due to the tarpaulins covering No. 3 
hatchway becoming damaged by the heavy water shipped on board and the washing away of the wooden 
hatch covers thus opening the hatchway to the sea, Numbers 8 and 4 holds were soon full of water and 
the ship foundered. 


N. Lost with all hands ona passage from the Tyne to Amsterdam loaded with a cargo of coal. 

This was a 245 ft. self-trimming collier of 1,550 gross tons, built in 1924: she had an extended raised 
quarter deck and a forecastle and between these erections was a broad trunk, on which was the No. 1 
hatchway. All the four hatchways were 25 ft, wide (65 per cent of the width of the ship) and their area 


52. 


represented a considerable percentage of the deck area; they had white wood double plank covers 18 
ins. by 3 ins. thick, each with two tarpaulins, cleats, battens and wedges; No. 1 had locking bars, the others 
had wire rope lashings: the lashing ropes and bars were prevented from damaging the tarpaulins hy 
chafing gear and parcelling. 


There being no survivors the exact cause of the loss could not be stated, but from the statements of 
the masters of seven other vessels in the vicinity at the same time as the “N” was likely to 
have been, heavy weather and confused seas were experienced. 


A sister ship had an entry in her log book that sea damage had been sustained, “heavy seas damaging 
No. 1 hatch, tearing off the middle and after locking bars, damaging tarpaulins and displacing wood covers, 
water entered No. 1 hold and vessel was compelled to return to place of shelter.” 


It also appears that there was not a sufficient number of deck hands available for division into two 
watches, and in the opinion of the Court‘ in this class of vessel with its exceptionally large hatchways, 
it is absolutely necessary that the security of the hatches should be well looked after, especially when the 
vessel is taking water on board. 


The finding of the Court was :—That in the absence of direct evidence the Court is unable to 
determine the exact cause of the casualty. 


O. Abandoned and lost during heavy weather in the Atlantic Ocean, with a cargo of grain. 
£ . g : 


This was a 382 ft. two-deck ship of 3,747 gross tons, built in 1902, with a poop, bridge and 
forecastle, four main hatchways and bunker hatchways on the bridge deck, 24 ins. and 3 ins. Baltic 
pine wood covers and the usual battening down arrangements. 


A heavy cross sea coming aboard dislodged an ice chest, which damaged a steering gear rod and put 
the ship out of control, consequently she fell off, bringing wind and sea on to her port beam, and 
shipping a lot of water. She took a list to starboard and the grain cargo shifted. Continuous 
heavy seas the next day washed wedges and battens from No. 3 and stripped the tarpaulins. The after 
bunker hatchway got stove in and water entered the engine room and stokehold; this hatchway was 
repaired and stove in three times. No. 3 now stove in and ship began to fill rapidly, the wedges of 
No. 4 now being washed out and two covers lost. Two days later all the hatchways were giving trouble 
and the ship had a list of 20 degrees; on the following day the list had increased to 30 degrees with the 
starboard hatch coamings constantly under water. The lifeboats had been smashed to bits by thie seas 
and another vessel which had arrived in response to the SOS call and had been standing by for two 
days was asked to send a lifeboat; this was done, but it capsized and two of her crew were drowned. 
The sea moderated slightly, another lifeboat was sent and the crew abandoned the vessel, which then had 
a list of about 50 degrees to starboard. 


The Court recommends that on winter passages additional security should be given when battening 
down hatches on weather decks by the use firstly, of folding wedges (also known as double or fox wedges). 
secondly of locking bars in suitable numbers and positions to secure hatch coverings. 


The finding of the Court was :—That the abandonment was attributable to the entry of water into 
the stokehold under the very exceptional weather conditions, which gradually increased the slight list 
caused originally by the shifting of the grain cargo. 


P. Presumably foundered, with all hands, on a passage with a cargo of coal, from Immingham to 
Odense, Denmark. 


This was a 245 ft. self-trimming collier of 1,522 gross tons, built in 1914. She was of the raised 
quarter deck type with bridge and forecastle and had four large hatchways, the breadth of one being 
72°5 per cent of the ship’s breadth, the area of the hatchways occupying 58 per cent of the deck area. 


In the absence of direct evidence, there being no survivors, no definite cause could be given, but 
from the reports of the masters of other ships which were in the vicinity in which this vessel would 
probably have been, stated that the weather was rough with snow squalls and fog. 


The finding of the Court was :—In the absence of direct evidence, the Court is unable to determine 
the exact cause of the casualty, but conjectures (1) that the vessel may have struck a point of land and 
afterwards sunk in deep water ; or (2) may have taken on board so much heavy water as to smash some of 
the hatch covers in the well deck and admit such a quantity of water as to cause the vessel to founder. 
But the Court does not consider the second alternative to happen (in the absence of mishap to machinery 
or steering gear) unless some of the hatchways or deck openings were insufficiently secured. The Court 
is of opinion that these large hatchways with wooden coyers are a positive source of danger, and that a 
vessel of that class proceeding to sea without her hatches being first properly and efficiently hattened 
down and secured, is not seaworthy. 


R. Foundered in the Atlantic Ocean during heavy weather whilst on a voyage with a cargo of coal, 


This was a 400 ft. shelter-deck cargo steamer of 5,832 tons gross, built in 1915; she had three decks 
and a forecastle ; on the shelter deck were five main cargo hatchways, a tonnage opening hatch and four 
side bunker hatchways. All were secured by means of wood covers, tarpaulins, cleats, battens and 
wedges, 

When the vessel sailed from Norfolk, Va., she was overloaded to the extent of 132 tons; after about 
four days out she encountered heavy weather, the tarpaulins covering the saddle bunker hatch were 
lifted by the wind but re-secured, the tar paulins covering the port bunker hatch were carried away, 
attempts by master and an apprentice to place fresh tarpaulins were made, the master was washed 
overboard and lost. Later the wood covers to this hatchway were washed away and water in large 
quantities entered the hatchway, giving the vessel a list w hich gradually increased, the vessel ultimately 
turning on her beam ends and foundering. One lifeboat managed to float clear away with 12 of the 
crew in it, and were picked up next day by another ship which had come in response to the SOS cail. 


The finding of the Court was :—That the cause of the foundering of the vessel was a large influx of 
water through the port bunker hatch, the covers of which were washed 2 away by heavy seas owing to the 
vessel having a heayy list to port and lacking reserve buoyancy in consequence of her overladen condition, 


S.  Foundered with all hands during heavy weather whilst on a voyage from Cardiff to Bordeaux 
with a cargo of coal. 

This was a 285 ft. self-trimming collier of 2,357 gross tons, built in 1918; she was of the raised 
quarter deck type with poop, bridge and forecastle; had four large sized hatchways, the breadth being 
65°5 per cent of the breadth of the s ship. The area of the two forward ones oce upied 57 per cent: of the 
area of the forward well deck, the after two 54 per cent of the area of the raised quarter deck. There 
were, including bunker hatchways, a total of 207 wood covers exposed to weather conditions, most of 
them double plank covers. About six months previously, during survey, 48 covers had been renewed 
and 34 repaired: she had tarpaulins, cleats, battens and wedges and wire lashings. 


Being classed as a self trimmer, only the coal in the hatchways was levelled off ; the percentage of 
space left after loading in the respective holds was:—No. 1, 19 per cent; No. 2, 8 per cent: No. 3, 
15 per cent; No. 4, 40 per cent. 

The vessel sailed and, according to the reports from several other ships, must have run into very 
foul weather; on the following day at 7.48 a.n. a wireless SOS message was received at Fishguard :— 
~ Off Hartland Point—require immediate assistance—hatches stove in—require immediate assistance.” At 
7.49 a.m. a message was sent: ‘Do you want lifeboat or boat to stand by.” At 7.50 a.m, the reply was 
~ Require anything—near sinking—trying launch lifeboat.” Nothing further was ever heard from her. 
During the next ten days the bodies of several members of the crew were washed ashore ; also some 81 
hatch covers which were identified as belonging to the lost vessel. These covers were thoroughly 
examined by a competent authority and appeared to have been broken in by the seas and the Court 
considered they lacked in strength. 


The Court is of opinion that definite provision and stipulations should be made in the specification 
for timber for hatch covers fitted in large and exposed hatchways and recommends that the wood should 
he of high grade, straight-grained timber, free from knots, shakes and sap. It is, however, strongly 
urged that the question of the use of steel in the construction of such covers should he considered. 


34 


The finding of the Court was :—That the cause of the foundering of the vessel was due to the large 
influx of water into two or more of the holds, owing to the force of heavy Seas breaking in the hatches 
during weather of exceptional violence. 


In the absence of direct evidence the Court cannot express a definite opinion, but it is probable ;— 


(1) that the cargo in Nos. 1 and 4 holds shifted, during the heavy weather, and thus caused a 
list which rendered the vessel more vulnerable to the impact of the seas : 

(2) that the breaking in of the hatches was caused by the inferior quality and defective condition 
of some of the hatch covers ; and 

(3) that in the heavy weather experienced, the large area of hatchways in proportion to the area 
of the deck constituted a serious danger and exposed the whole of the hatches to 
exceptional strain. 


T. Lost with all hands during a voyage from Hamburg to Hull with a general cargo. 


This was a 240 ft. cargo ship of 1,107 gross tons and was built in 1930. She hada poop, bridge 
and forecastle, the after well had bulwarks & ft. high and the space between the bridge deck and the 
poop deck which was 19 ft. long was covered by unsecured hatches in two lengths, 18 ins. wide by 2 ins. 
thick. She had three cargo hatchways covered with 3 ins. wood covers, tarpaulins and the usual 
battening arrangements. 


When the vessel left the Elbe the weather was fine, but, according to the reports of other ships and 
a lightship, there was a strong wind, and a heavy swell with rough broken seas. On the following day : 
number of the unsecured hatches, two lifeboats and other wreckage was found and identified as belonging 
to this vessel. 


The vessel did not carry a wireless installation. 


The finding of the Court was :—There is no conclusive evidence as to the actual cause of the loss, 
but the most probable cause was that the ship was overwhelmed by a heavy sea which carried away the 
unsecured hatches aft and partially flooded the bridge spave, thus very quickly destroying her stability so 
that she capsized and sank in the North Sea. 


VU. Lost during a hurricane in the North Atlantic Ocean whilst on a voyage from Montreal to 
Queenstown with a cargo of wheat, partly in bulk and partly bagged. 


This was a 356 ft. single deck steamer of 3,535 tons gross and built in 1926, she had five main 
hatchways, wood covers, tarpanlins and the usual battening arrangements. 


After a few days out, a heavy sea stove in the saloon door and the ship was hove-to to effect repairs, 
later it was found that the steering gear had been carried away and wireless messages for help were sent 
out. To assist in the steering a cable was made fast to the stern from another vessel which arrived on 
the scene. liater the cable parted, the wind had increased and high confused seas were breaking 
over the decks, deck fittings were carried away, No. 2 hatchway tarpaulin was dislodged but resecured, 
the bridge front was stove in and during the night water entered the stokehold by a bunker hatchway. 
No. 2 hatchway coamings now buckled, three web beams forced down on to the grain and wood covers 
broken and washed away. The water in the stokehold reached the boiler furnaces and extinguished the 
fires. The list, about 25 degrees and still increasing, and when tie bulwarks and decks were under 
water, a lifeboat was sent from the second vessel and took some of the crew off; it, however, capsized 
and 14 of the occupants were drowned. Later a third vessel arrived and sent a boat to take off the 
remainder, but a further three of the crew were lost in this effort. 

The outstanding topics at the inquiry were the type and efficiency of her main steering gear and 
the failure of her auxiliary steering gear. The structure of the hatches, and whether they should have 
been of steel rather than of wood were subjects of argument. 

The finding of the Court was ;—That the vessel was overwhelmed by the sea and foundered in 
a hurricane, 


35 


V. Lost with all hands, during bad weather in the North Atlantic Ocean, whilst on a voyage 
from Swansea to Boston, U.S.A., with a cargo of anthracite duff, 
: ; g 


This was a 338 ft. single deck ship of 3,259 gross tons, built in 1924; she had five main hatchways. 


Ten days after leaving Swansea bad weather was encountered and although there were no survivors, 
the cause of her foundering was very clearly indicated in a number of wireless messages which were 
. . ba . e . bs S 
picked up by several ships during the night :— 


5.52 “Steering gear gone: forward hatch stove in.” 


6.10 “No, 1 and No, 2 hatches stove in.” 
6.57 ** Mountainous head sea; terrific squalls : hove to at: present.” 
8.14 “Rolling in trough of sea; engine room makes water; engines not going : repairing No. 2 


hatch and drifting : require ships to stand by. 


8.30 “Temporarily repairing No. 2 hatch ; endeavouring to secure forward watertight bulkhead.’, 


yee 


No. 1 hatch and No. 5 stove in; No. 2 temporarily repaired ; now trying to shore up 
watertight door forward.” 


11.11 * We are now in desperate circumstances; No. 2 hold is full of water and pumps cannot 
keep up with it.” 


J ? 
WL 


0.8 ‘Pretty hopeless; don’t think we can last another 15 minutes : lying right over on side : 
hugh seas coming aboard every second.” 


Ship listing badly to port: taking heavy seas.’ 


Nothing further was heard except her SOS signals which gradually died away, and the answering 
ships, on their arrival, only saw a smal! quantity of wreakage. 


There was much conflict of evidence at the inquiry as to the covering and security of the hatchways 
and the condition of the covers and their fittings and coamings: there were wear and tear defects, but 
the coverings had been of the required thickness when supplied ; cleats, battens and wedges were available 
and in good condition : the tarpaulins were of diverse quality but sufficient under normal conditions, 


The finding of the Court was:—Uhat the vessel foundered in weather of hurricane force. 


W. Lost with all hands during heavy weather, in the North Atlantic, when proceeding fully laden 
with a cargo of rye, from Dantzig to Montreal. 


This was a 355 ft. steel cargo ship of 4,222 tons gross, built in 1906; she had four main hatch ways. 

There being no survivors the cause of the foundering is traced from thé wireless nessages she sent out. 

* Continuous bad weather ”—* Cannot make progress owing to heavy gale” —* Water entering No, | 
hold, cannot locate ”’—* Helpless, driving before hurricane” and later she was sending out SOS signals, 
then * After hatch stove in, three men injured, driving helpless before gale.” After this the messages 
hecame too weak to read. lwo of the rescue ships arrived at the last given position and searched the 
area without result. 

One of the rescue ships, encountered the same storm and received such deck damage (her No. 1 
hatch and forward bulkhead were stove in and ventilators swept away) that she had to return to Cork. 

The master of the other rescue ship, said, “ It seems impossible that any helpless ship with her hatch 
stove in could live in the trough of such a sea.” 

According to the evidence regarding the hatchway coverings, they were as one might expect to find 
ina ship of her age, that is, they were not new but with the replacements from time to time they were 
sufficient and adequate for the voyage. 

The finding of the Court was :—That the cause of the loss of the vessel was the perils of the sea 
and, in particular, the eather in which she sank. 


XM. Lost with all hands in severe weather in the North Atlantic Ocean during a voyage from the 
United Kingdom with a cargo of coal. 


36 


This was a 423 ft. single screw two deck cargo ship of 5,785 gross tons. 

There is no definite knowledge as to what happened to cause the loss of this vessel, and very little 
enlightenment in the few wireless messages received before she disappeared. After six days out, she 
sent out a general urgent message giving “her position and stating * Whole gale, ships in vicinity please 
indicate position.” The next mor ning she sent out an SOS signal and * Wanting immediate assistance. 
Have taken dangerous list.” This was followed in seven minutes by “* Now abandoning ship.” 


With regard to the hatchways, the report states that when the vessel left the United Kingdom, the 
hatchways were adequately protected and secured, that the hatch covers were sufficient and in good 
condition and that the tarpaulins and battening down appliances were in good condition, and sufficient 
for the purpose of the intended voyage, also with regard to the latter, provision was made in excess of 
ordinary requirements, 


It appears that in the previous summer cattle decks which had protected the hatchways in the 
forward well were removed and immediately afterwards the master reported his uneasiness regarding the 
security of these hatches, and requested additional precaution, which was at once conceded by the 
owners. 


The report states, whether the casualty was caused by shifting of cargo or by influx of water 
through failure of a hatch, or by a combination of both circumstances, there is evidence to justify a 
doubt as to whether existing regulations are adequate as regards “height of platform,” or, more properly, 
in this case, “height of most v uinerable region.” In expressing this doubt, due regard has been paid to 
the fact that publishe dl statistics of losses have shown decrease of danger; but regard has also been paid 
to the fact that several recent casualties can be ascribed largely to failure of hatches. These failures 
have occurred in ships of the same general type. 

The finding of the Court was :—That the canse of the loss of the ship was necessarily a matter of 
conjecture. 

. 

Y. Lost, in heavy weather, in the North Sea, during a voyage with a cargo of small coal (peas 
and duff). 

This was a 280 ft. self-trimming collier, of 2,001 tons gross, which had six large hatchways, feeding 
four holds. 


When this vessel sailed, with all her hatches properly battened down, she had a small list to port of 
2 degrees; later in the same day she encountered heavy weather, and the seas, coming over the decks. 
washed the wedges and tarpaulins out of the cleats of Nos. 2 and 3 hatchways: these were re-secured, 
but the trouble recurred so often that 200 spare hatch wedges were used up. With the entry of water 
into the holds and the shifting of the cargo, the ship ultimately had a list of about 35 degrees. The 
master decided to abandon the ship, which was done without loss of life, and the crew were picked up 
hy one of the vessels which had answered the SOS call. 


The wholesale washing out of the wedges from hatch coaming cleats is an unusual and unexpected 
occurrence; the cleats in this case, and in most old ships, were parallel to the coamings; the Board of 
Trade now recommend cleats to be set at an angle to the coaming. 

The finding of the Court was:—That the loss of the ship was due to the shifting of the cargo 

caused by the heavy labouring of the vessel during the exceptionally heavy weather and the entry of 
sige in Nos. 2 and 3 holds. 


APPENDIX II. 
Extracts from Lloyd’s Daily Casualty List. 


I S, Poop door stove in, tarpaulin of No. 8 hatchway torn away. 
2 be Hatches and bulwarks carricd away and four persons drowned. 
3 — Heavy weather, first four tiers of rice wet in No. 5 hold, presumably from 
hatchway. - 
| a Heavy weather, 15 ins. water in starboard bilges of No. 4 hold. The water 
had penetrated into the starboard coaming from No. 2 “tween deck hatch. 
5 xe Heavy weather encountered, a forward hatch cover broke loose, Boatswain 
killed and three of crew injured in repairing damage. 
(5 a Vessel stranded in heavy weather, No. 2 hatch broken in. 
7 aH A heavy sea washed the lifeboat, hatch tarpaulin and deck gear away, vessel 
subsequently drifted ashore and became a total wreck. 
x awe Encountered a severe typhoon, hatches stove in, flooded athwartship bunkers 
and “tween deck. 
a) Ae Took a dangerous list in a gale, abandoned, ail hands lost. Hatch failure 
probable cause. 
10 we Heavy weather, lost with 15 hands, possibly hatches. 
11 “te Heavy weather, after peak hatch stove in, 
2 eh Tarpautin of No. 1 hatch ripped off, iron strongbacks of No, 2 bent and twisted 
and other damage. 
Is aes Heavy weather, tarpaulins of Nos. 1 and 2 hatches damaged, water penetrated 
into No. 1 hold. 
I4 res Heavy weather, damage to hatch covers. 
15 = Heavy weather, tarpaulins damaged Nos, 3, + and 6 hatches. 
16 AB Heavy weather, 142 bags of wheat completely spoilt by sea water. 
17 nas Heavy weather, hatch boards broken and tarpaulins torn away from Nos. 3 and 4 
hatches, 
1s te Lost with all hands in bad weather, possibly hatches. 
i) oe Owners fined £200 for neglecting to secure hatch beams. 
20 58 Owners sued by widow for loss of husband due to faulty hatch cover. 
21 he After hatch badly damaged, sea water penetrated into hold and damaged sugar 
cargo, 
22 = Sea water in Nos. 1, 2 and 3 holds. 
23 No. L hatch tarpaulin washed adrift by heavy seas, water in ‘tween decks, cargo 


damaged by salt water. 


24 a No. 2 hatch stove in. 
25 on Heavy weather, hatches and tarpaulins damaged. 
26 During the storm the pounding of the seas opened the hatch of No. 2 hold and 


tons of water poured in threatening the vessel. 

27 eRe During a lull in the storm the master decided to further safeguard the No. 1 
hatchway, whilst doing so a heavy sea swept the ship, killed three men and 
injured four others. 

28 re Tarpaulins of Nos. | and 3 holds torn away and wood covers broken, water 
entered the hold. 


38 


During heavy weather, tarpaulins of No. 5 hold damaged, water penetrated 
hold damaging a large number of bales of tobacco, 

Experienced bad weather, tarpaulins of No. 2 hatch torn and water entered hold 
partly damaging the cargo. 

Very heavy weather, No. 2 hatch stove in, managed to turn vessel round and 
running with following sea. Managing temporary repairs to cover of fore 
hatch. 

Experienced heavy weather, tarpaulins were torn. The tarpaulins to No. 2 

hold were upheaved and the hatch covers displaced. 

During heavy weather damage to deck fittings and hatches. 

Experienced heavy weather during which tarpaulins of No. 2 hold were torn. 

Experienced heavy weather during which two tarpaulins of No. 1 hatch were torn. 

Put back to port with No. 1 hatch stove in. 

Foremast sprung and two plates buckled, owing to winch putting extra strain 
on to dislodge the No. 1 hatch beam which had become jammed in the slide 
angles. 

Fore hatches stove in by heavy seas. Abandoned. 

Heavy weather, water entered Nos. 1 and 2 holds, cargo damaged. 

Very stormy, covers and hatches washed off and cargo seriously affected. 

Heavy weather, hatch tarpaulin torn away. 

Fire in aft hold, several wood covers and tarpaulins destroyed by fire. 

Shipped heavy seas, hatch covers ripped off. 

Aground and all hatch boards and covers washed off. 

Heavy weather, hatches broken open by the seas, vessel sank in five minutes. 
Nine lives lost. 

Fire in No. 2 hold, two tarpaulins burnt and wood covers scorched. 


WeB PLATE 


EXTENSION ON 
ALTERNATE 
BEAMS 


Cieats spaced 2 & 2 TARPAULINS 


6" From CoRNERS i 


2%" Wood CovERS 


x 
=k 


AMET ME PTL MM A MRE ME. 


| 20 
DEPTH AT 
CENTRE 
SUPPORTS 1, N ; 
Sar 1 mean 
every | J N PACKING PIECE Between watts 4 
10 FEET , af N SLIDE ANGLES To PRowoeE TRGLES 
N 3 BEARING FOR BEAMS 
N 
N 
N 
N 
N 
N 
Ny 


SZ 


Fie. 1. ARRANGEMENT AS CONTEMPLATED BY THE CONVENTION RULES. 


COAMING *. BATTENING (Rot 


Fic. 2. Frrrrve oF Woop WEbDGEs. 


AFTER HatcRw. 
ATES STA COAMING y FoRWARD HATCHWAYS 


eee Caer 


B.A. STIFFER 


Fie. 38. Lue Creatrs—Usuan ARRANGEMENT. 


ALL HATCHWaAYyS 
pee ee eo A ee 
le Ss Ss Ss Se Ss ese Ss 


Fie. 4. Proposep Lue Crear ARRANGEMENT. 


RING BOLTS 


VM 


Enos SECURED 


To WINCH 
oR ANY 
OTHER 
CONVENIENT 
FITTING 
we ty ey } 


Fig. 5. LasHincs on a Connrer’s Harcuway. 


> 
Ee ee) SS», 


ai 


STRETCHING. Sceews 


( LASHINGS PARCELLED aT ConminGs Hs SW.R . 


I" SvRETCHING ScREW 


Fic. 6. PLAN AND SECTION SHOWING LASHINGS WITH STRETCHING SCREWS. 


‘ma i 


SAFETY Lock 


INSIDE of HATCHWAY 
PERFECTLY’ FLUSH 


“No ANGLE OBSTRUCTIONS 


GREATER PROTECTION _— 

Deck STEAM PIPES 
RECESSED | 
COAMING | 

Fiq. 7. PREVENTS 
HATCH | 
DAMAGE | 


ry PoaraBle 
begat Rowing 
~ GEAR 


STRONG 
& RowteRr 
TRACK 


= SELF 
CENTERING 
Pack | 


LEVER FoR RAISING HATCH 
BEAM FoR PoLiNne 


» 


Fic. 9. 


Fic. 10. 


Kira. 11 


Double cover with vertical reinforcing plate between joints (weight of plate less 
than | Ib. per foot) and fitted with either closed End Shoes or open End Bands. 


SSE 5s 
AS Nore 


Mild Steel Galvanized open End Band with Beaded Edges Mild Steel Galvanized closed End Shoe 


Fic. 18. A, B ann C. 


SECTION SHOWING 
TURNBUCKLE FITTED TO 
$ LOCKING 


VV TT eecii0N SHOWING 


ECURING COVERS AT ENDS ___ aaa 


wooD COVERS INSERTED FOR COMPARISON C 
SS » (Se eae 


eH 


SLAB TYPE OF WOOD HATCH COVER 


. 
y 

Yo 
Y as 

os 

es 
= 
oe 
“«<» 
denne aes 
oe 
oe Lifting rene 
> . 5 ~ 
‘ ~ 
+ se os => 
- ao - oF, ~ 
ae » . 
SF 
. . ° 
= 
- » o 
> . > ~ 
~ pm 
~ 2 
. “ 

a a 

——S a 


Ont aon 


Lenger "2. andth of Rat 


Width Spacing of baa 


Iheck ness. 


mw Cover 


oneay 


ms 


Zeer D according to Spacing of beams 


Fig. 2: 


bd 
| 
—f#' | 
° j 
2g a 
= | 
ot 
we! 
o 


Horiz* BANGLE PACKING 


TRACK FOR WHEELS COAMING 


Fig. 29. SECTION THROUGH COAMING, 


FOR Covers Fias. 25 To 28. 


J'ow. Tossle 


ri 


4 a nS i 


PLATE COVER 


GREASY HEMP 


4 
y) 
y PACKING 


COAMING 


Fig. 31. SKOTION THROUGH COAMING, 
FOR Cover Fia. 30. 


ihe owe 
oy en noe ae 


elem 


SPACE FoR 
SoFT PACKING 


rs x3 ThE BAR 
SuPPORTS . 


a fe bry, es 2a raeshk 
> iC ) | 

om = 
= (Cie 


Jr Fa, Baax 


Section Tees Gaur T 


Cuawwel in Way OF Cowes 3 


—— ---- — - = den MOT ot Ube 


OC Pran Yew OF Exo oF 
ns i GasweT Coanmes 


Gases T \ Cuameet 
firs 


1 Ore Pose 


Leven up foce of © 

forge ite Tronong 

Seekers en 
Coram Prate 


“) beg SeerTeo 


Sree Pageme To iS ) 
Te Tane Tecote 


%% 


Wows ng To Moco 


CpaqurTian Pos Ton 
Yoemannci  SustTreg 


ELevaTion 


Tecate Conneclion AND Mince on SuuTTer AT Maren Sives £ Enos 


ni or 
Fic. 87. 


pe 
a eer ee F 


Fig. 


EL 


COVER 


ACOA MING 


SECTION 


COAMING. 


THROUGH 


RESILIENT FAcKiNG 


COVER 


Fic. 42. SECTION THROUGH 
Cover JOINT. 


ELEVATION OF HATCH SIDE SHOWING COVERS IN POSITION 


CAPTIVE WEDGES _ ; pineo creas 
ATTENING WITH CAPTIVE 

RUBBER SEAL AXLE /GUTTER “WEDGES 

ER SNPS COVER {ow W°2 COVER = N°! CovERd 

| ee ae ae =P 


HINGED CLEATS 


DECK MOUSE! 

oa \ 
DECK 

ERECTION 


F Stick® Ti 
DECK ATIMATCH Si 


HA COAMINGS B 
ULB PLATE UPPE 
| 2° 6°HIGM AT CORNERS — CoamING WITH STRAIGHT SHEER Deckiarae 


e—— — — 34'0” CLEAR LENGTH OF HATCHWAY — — — — ——-— —-»+- 4. 6 = 


Fie. 48: 


Fra. 46. 


The batteniny bar is 


paulin by swinging wood su 


ed hard 


wis (working something 


ast the tar- 


like a wedge), strengthene by plates and locked 
with a special spanner The arrangement is very 


effective, timesaving and cheap 


1s 


A TANKER IN 


A 


SEAWAY. 


DISCUSSION on Mr. J. G. BUCHANAN’S PAPER 


ON 


HATCHWAYS. 


W. Wart. 


The writer is to be congratulated on bringing before the Association a subject so topical as hatchways. 
Perhaps there is no part of a ship's structure “which contains such a potential source of danger and 
therefore it behoves us to give the subject the fullest consideration. This is more important in these 
inodern days when hatchways are of such dimensions as almost to constitute portable decks. 


I am in the fullest sympathy with the author in his contentions regarding the use of steel watertight 
hatches and I hope the time will soon come when steel covers will become the usual thing. At the same 
time I think the author has gone out of his way to flog the wood covered hatchway and all who have had 
anything to do with its use. He should remember that a good case needs no special pleading. 


On page | he says that * until 1932 there were no statutory detailed regulations for the construction 
and closing hatchways.” Some of us wish that there were no detailed “rules for anything and the 
development of steel covers is surely an instance of the absence of detailed rules helping ‘development. 


It is a commonplace remark that when regulations enter common sense steps out and I realise the 
truth of this every day. It might be claimed that prior to 19382 there were no detailed statutory 
freeboard regulations, for the regulations in force were framed by the Board of Trade under powers 
conferred upon them by the statutes. 


[ would like to ask the author if he can point to a defective arrangement having been approved by 
the Board of Trade. 


Further, the author states that the fitting of steel watertight hatch covers is not considered to be 
absolutely care-free, but gives his case. away in a previous pare agraph when he said that ‘it is not contended 
that the strength or arrangement of the system (wood hatches) is deficient or unsatisfactory.” 


It is alla matter of upkeep. Granted the life of a wood cover is shorter than that of a large steel 
cover, but wood can be got at any port and be fitted by anyone, and modern wood covers are not made of 
such poor timber as the ‘author suggests. 


At a recent enquiry one of the assessors stated that in 40 years experience at sea he had never seen a 
hatch stove in, and the captain of the lost steamer reported that in 47 years experience neither had he. 


It has been stated, and the author supports the statement that the end coamings when unstiffened 
are frequently set in by a wave rebounding say from the bridge front, but enquiries at some of the 
outports revealed that no surveyor at any of these ports had seen such an occurrence. Again it is a 
question of condition and ace ‘idents are usually caused by failure to make proper use of the facilities 
provided. —[ repeat my preference for steel covers but the old wood cover is not so bad as it is painted 
and like the restive horse is all right when properly harnessed. 


On page 5 the author says that for many years prior to 1932 the lack of uniformity in international 
freeboard assignment was apparent. But was it? All the regulations in force gave freeboards within an 
inch of one another with the exception of a limited class of Norwegian ships which got a freeboard of 
| to 3 ins. less than the same ships in other countries. 


» 


The author advances a plea for deeper loading for cargo ships having steel covers on the basis of the 
allowance which is given for tankers. But is there any logical comparison ? The tanker has very small 
hatches which are easily kept watertight while the cargo ship is all hatchway; the tanker has a high 
degree of subdivision and a pierced tank will hardly affect its seaworthiness, but the same cannot be said 
of the cargo ship; the tanker requires a very strong overhead gangway to enable the crew to get back- 
ward and forward to their work : would the author suggest such a gangway for the cargo ship? Many 
owners and captains expressed their disagreement with the deeper loading allowed for tankers and they 
ought to know. 

Freeboard is intended to provide a margin of safety and a sufficient height of platform to enable the 
crew to perform their duties with safety. It is not a question of reserve buoyancy as the author suggests 
and one of the committees stated especially that reserve buoyancy was not a factor in determining 
freeboard. 

The author advances a plausible argument on the basis of the allowance for detached superstructures . 
but look at it from another point of view, viz., that a given allowance is made for a complete super- 
structure and a penalty is imposed for shorter superstructures and his argument falls to the ground, — It 
must be remembered that regulations framed, as all regulations must be, on broad principles cannot be 
logical to the nth degree. 

The author has devoted a large part of his paper to the reports of courts of enquiry. I haye 
probably attended more of these enquiries than anyone here and have a great regard for the way in which 
these enquiries are conducted, but with all respect I suggest that they do not always arrive at the truth. 
To take one example which is referred to in the paper under a letter of the alphabet, the court found that 
the vessel was lost because the hatches were smashed and water entered the hold. 

A peculiarity of the fracture was that it was in a straight line across the hatch. Along with others 
I inspected the broken hatches after the enquiry and was deeply impressed with the result. 

But I changed my opinion when at a later date evidence was given to me, and after investigation I 
accepted it, that the portions of hatches washed ashore were never used in the ship but were rejected 
hatches which had been placed across an angle bar and were broken by dropping weights on them, the 
pieces being stowed on board for other uses. 


In the case in which it is stated that 200 spare wedges were used up, the captain in the witness box 
explained * when you are hammering a wedge with one hand and holding on with the other, you cannot 
grasp a bag of wedges and so they went overboard.” 


In another case the court of enquiry found the owners to blame for the loss of the ship but at the 
Old Bailey the judge found that there was no case to go to a jury and the witnesses for the defence were 
never called. 

The collection of prints of the various types of steel covers is the most valuable part of the paper 
and for this alone the author deserves our best thanks. 


W. THomson. 

The subject of this paper, the protection of deck openings, as affecting the safety of a ship Is one 
that has exercised the minds of naval architects for many years. One of the earliest references on 
this point is to be found in the recommendations of a Special Committee on the Safety of Ships appointed 
by the Institution of Naval Architects in 1866, which suggested, among other items, that :—* It is 
desirable to carry the beams of the ship across the hatchways without interruption wherever practicable— 
the beams may be removable where required, being replaced on going to sea.” 

I do not suppose the arrangement outlined above was ever adopted, and there is no doubt that in 
those early years the means adopted for closing the hatchways were decidedly primitive. Since then, 
however, progressive improvements in the structure of hatchways has taken place, all lucidly detailed in 
the paper, culminating in the present official regulations. In entire disagreement with the author I would 
venture to suggest that modern methods of closing hatchways leave little to be desired from the point of 
view of security as affecting the safety of the ship. It is far too common a practice to assign, very 
often without any evidence whatever, the cause of the loss of a ship to the hatchways being stove in. 
There can be no question as to the strength of the hatch webs and the question is thus narrowed down to 
the strength of the wood covers. 


2 
” 


From a rough calculation it would appear that these would withstand a head of water of, say, 18 feet, 
which seems to allow an ample margin, including the dynamic effect of the water falling on the hatches. 
When one considers the thousands of ships continually at sea, each with several hatchways, | think it is 
a high testimonial to the modern hatchway that so few cases of damage are heard of. The author gives 
a list of typical cases of loss at sea attributed to failure of the hatchways, but an examination of this list 
proves very unconvincing. 

With a view to getting some idea of the importance of the subject I turned to the authority, quoted 
in the paper, the report of the Load Line Committee of 1915. As stated by the author this report says 
that 18 per cent of the losses at sea of British ships were due to failure of the hatchways. This at first 
sight seems impressive, but a little further investigation of the report shows that the average number of 
ships, foundered or missing, was 17 per year, icluding vessels of under 100 tons gross; 18 per cent 
of this number means that the loss due to the unsatisfactory construction or inefficient use of the 
closing appliances was two vessels per year. These figures relate to the period prior to 1915, and it is 
probable that with the increased requirements now in force, the figure will now be rather less. 


While this is no reason for not endeavouring to improve the hatchways, it makes it clear that there 
is no foundation for the alarmist tone running through the paper and that the field for improving 
the rate of loss from this cause is very small indeed. 

From the same standpoint the following extract, which appeared in the Press this week, dealing with 
the question of insurance rates, a point on which the author lays some stress, may be of interest. 


Some Reassurtnc Figures.—In 1934 the annual return of casualties compiled by the 
Liverpool Underwriters’ Association showed that out of 5,203 casualties recorded only 19 came 
under the heading of “foundering and abandonments,” and if to these are added the seven 
cases of “missing,” the total only reaches 26. In 1935 the figures show 28 “founderings and 
abandonments ” and seven “ missing,” a total of 30 out of 5,560 casualties recorded. Not all of 
these foundering and abandonments were caused by stoye-in hatches, nor, possibly, all the cases 
of “missing,” but taking the figures as they stand, it would seem that in their respective years 
the percentages of the total of recorded casualties attaching to the causes of loss in question were 
0-0 and 0-54. Lf we call the proportion of casualty one-half of one per cent it is near enough. 

Now it would be unfair to apply this percentage to the rates for ‘ total loss only,” because 
the figures given include casualties of all kinds ; so to arrive at a very rough estimate of the rate 
to allocate to the risk of foundering the percentage can be applied to the full sea peril rate. This 
means that on a risk rated at £5 per cent, the “ foundering and abandonment ” rate could be called 
Gd per cent. Ona risk rated at 75s per cent the rate would be 43d per cent, and on one rated at 
50s per cent only 3d per cent could be allocated to the * foundering ” risk, and it must be borne 
in mind that the figures on which this computation is based include founderings from causes other 
than stove-in hatches. 


K. W. BLooxstpGr. 

Mr. Buchanan deserves the thanks of the members of the Staff Association for bringing before our 
notice and for our discussion a subject of great importance, viz., the methods employed to close and keep 
closed, while the ship is at sea, the most vulnerable places in the hulls of vessels, viz., the hatchways or 
entrances to the cargo holds, and also for his confident and open criticism of the arrangements fitted on 
present-day ships. 

The demand for large hatchways is increasing as the requirements of shipowners are becoming more 
exacting to deal with the expanding and varied types of cargo to be carried. The Board of Trade and 
this Society have been and are fully aware of the necessity to deal with the general question of hatchways 
in relation to the demands of trade, and Circular 166, issued by the Board of Trade in September, 1927, 
draws special attention to the necessity of providing adequate protection to the hatchways on coal- 
carrying vessels. 

The application of the principle underlying the freeboard regulations in regard to the closing of 
openings leading into superstructures situated on the freeboard deck depends upon the vulnerability of 
that erection. If these superstructures are to be maintained in an intact condition to keep out water and 
preserve a dry space for the accommodation of cargo, we would never dream of permitting wooden storm 


4 


boards to be fitted in riveted channels to the full height of the openings, although these channels do 
prevent the boards being displaced by storm water. Such a space must not be fitted with temporary 
means of closing at their openings, but have permanent fittings such as hinged weathertight doors. Yet 
in the case of hatchways situated on the freeboard deck and leading to intact spaces which are the most 
vulnerable in the ship, the convention regulations permit these openings to be closed with wood covers, 
provided the finished thickness is at least 22 ins. in association with a span of not more than 5 feet. 


In this respect the Society’s rules do not stipulate of what material the covers shall be made and 
only refer to “solid” covers. Without additional means fitted for preventing the covers lifting the 
covers are definitely inferior to storm boards in riveted channels. 


It is in regard to these additional means of security which is the cause of so much controversy at 
the moment. 


I do not quite agree with Mr. Buchanan when he states that the material usually used for hatches is 
Pinus Sylvestris or otherwise known as white, red or yellow pine. This is known as Baltic redwood and 
is, actually, the European pine of the northern districts, but certainly not yellow pine and generally 
referred to in this country as yellow deal, a fairly strong and durable wood in exposed positions. 
Baltic whitewood (Picoa Ezcelia), known in this country as the white deal, spruce or fir, grows in the 
same districts as the redwood but is inferior in quality, and is the material which is usually employed in 
making hatchway covers and possesses all the characteristics referred to by Mr. Buchanan. 


The wood covers would be efficient if they could be held in position by riveted or welded channels 
and are of good quality material. 


The reason for the movement of the wood covers is due, according to the reports of enquiries and 
the accumulated evidence in this office, to the inadequacy of the hatchway coamings to take the stress of 
a green sea under unusual conditions of service, and thus allow the covers or the hatch beams to become 
unshipped from their bearing surfaces. Immediately this occurs, tarpaulins and lashings are of little 
avail to prevent the holds from being filled with free water. It would seem to point to the necessity of all 
upper deck hatchways being additionally stiffened by the fitting of closer spaced stays or brackets, i.e., 
less than the 10 feet permitted by the rules. 


The efficiency of any system of hatchway covers can best be seen from the results of the periodical 
surveys demanded by the freeboard regulations, and since the annual and renewal surveys have been in 
operation for about three years we have abundant evidence as showing the necessity for a very careful 
oversight on the part of surveyors when dealing with the details of hatchways and their closing appliances. 


I have taken a few cases which have come under my personal notice when examining the reports 
forwarded to this office from the outports. These are typical of many and are selected at random. 
(a) A ship carrying ordinary cargo. Eighty hatch covers renewed and a large number of 
cleats found defective and renewed. 
(b) A ship carrying timber deck cargoes. About 200 hatch covers renewed and a corresponding 
number of cleats renewed, hatchway coamings, stiffeners and shifting beams found defective and 
repaired or renewed. 


(c) Another ship carrying ordinary cargoes. Over 100 hatch covers renewed, a great number 
of cleats renewed and coaming plates renewed. 

(¢) A similar ship to (c). 86 shelter deck hatch covers renewed, 60 cleats renewed, a number 
of mounting angles to the shifting beams renewed, and 9 hatchway end stiffening bars renewed. 


The amount of replacements, renewals, and repairs required, considering the frequency of the 
periodical surveys, makes one feel that it would be to the shipowners’ advantages, financially and in other 
respects, to adopt some better method of closing the hatchways than by the ordinary wood covers, although 
the capital outlay would be greater. 


The amount of repairs in the case of ships carrying timber deck cargoes and which obtain deeper 
loading than the ordinary cargo ship is more extensive than would appear to justify this deeper loading 
having in view the type of hatchways usually fitted. In the case of tankers, however, where the 
hatchways are of course very much smaller, but are closed by watertight steel covers, the repairs are 
almost negligible, to judge from the reports of the surveyors. 


There is only one other point I wish to refer, and that relates to paragraph 2 on page 16. The 
author draws our attention to the question of tonnage openings in shelter decks and the attitude of the 
Panama Canal authorities. The Panama Canal as well as the Suez Canal tonnage regulations do not 
recognise deck tonnage openings or the exemption of shelter tween decks from tonnage measurement. 
The Panama Canal authorities are only concerned with tonnage openings when the regulations of 
the United States of America are being administered for ships passing through the canal, and they are 
unable to enforce the application of their own regulations. 

There are other phases of the subject which could be referred to, but time does not permit for these 
to be dealt with, and there is little doubt they will be fully discussed here to-night, or among the outport 
members whose practical experience will add greatly to the value of a paper which has been written by 
Mr. Buchanan, a member with an intimate association with his subject, and presented in a clear and 
straight-forward way, which, nevertheless, is bound to create a wide expression of opinion, a result with 
Which he will be perfectly satisfied. 

S. T. BryDEN. 

In the last paragraph of page 1 of his paper Mr. Buchanan quotes paragraph 24 of the pre- 
Convention Freehoard Regulations as being the only statutory regulations for the construction and 
closing of hatchways before the year 1932. This is not the case, however, as in Rules for the 
Determination of the Freeboard of the Shelter-decked Steamers, clause 7, in the same regulations, and 
Board of Trade circular No, 1416 clause 6, published in 1907, requirements are made as to the provision 
in hatchways of hatch rest bars, cleats and battening down bars, thwartship beams and fore and afters, 
substantial hatch covers and tarpaulins. 

Although there can be no serious defence of the old system of hatch covers supported by beams and 
fore-and-afters as applied to hatchways of large size, improvement in the means of closing of hatchways 
has been a continuous though slow process. The trend has been to reduce the number of parts, and the 
slab covers shown in Fig. 20 appears to be the most efficient type of wood cover yet produced. 

There can be no doubt that steel hatch covers are more efficient and less liable to damage than wood 
covers, but the thickness (or rather the thinness) of some of the small steel covers, used with tarpaulins, 
leaves one in doubt as to their stiffness and durability. The provision of large steel covers which can be 
secured watertight or weathertight without the aid of tarpaulins is undoubtedly the ideal arrangement, 
provided the covers are of sufficient strength and the fastening arrangements are efficient. A large steel 
cover distorted by heavy weather or other damage, and provided with an insufficient number of fasteners 
to maintain the weathertightness of its perimeter, would be useless. 

The patentee of the covers which are indicated in Figs. 14 and 16 appears to be labouring under a 
misapprehension as to the chief purpose of lashings and locking bars, which are required primarily to 
prevent the tarpaulins ballooning through wind getting below their surface and tearing them out of 
their battens. 

The arrangement indicated in the Board of Trade Circular No. 1665 for special lashings in the case 
of ships having very wide hatchways appears to be very sound where the covers are laid fore and aft, but 
when they are laid athwartships the requirement for athwartship lashings, only when the length of 
hatchway exceeds 30 ft., is adequate. When the lashings are set up with Warwick screws, shields of 
leather or other material should always be fitted between the lashings and tarpaulins on the edge of the 
hatchways to prevent damage to the tarpaulins. Lashings should always be “independent.” A lashing 
which is attached to one eyeplate and carried continuously through the other eyeplates, backwards and 
forwards across the hatchway, is useless if it breaks at any part. 

Iam in agreement with Mr. Buchanan where he suggests, on page 8, that the end coamings of large 
hatchways should be stiffened even when they are protected, as a blow on the stiffened side coamings 
would probably cause bulging outwards of the unstiffened end coamings. His reasoning against. the 
suggestion that cleats should be so angled that the thick end of the wedges should alternately face forward 
and aft is also very sound. 

The reference on page 12 to the increase in size of hatchways in recent years is illustrated by a case 
dealt with a short time ago, where a ship 235 ft. by 45 ft. by 15°5 ft. had a hatchway 96 ft. by 24 ft., 
having ordinary wood covers. The tarpaulins for this hatchway were in one piece, but an efficient 
arrangement of special lashings was provided. Mr. Buchanan’s proposal for a divided hatchway in self- 
trimming colliers merits serious attention. 


6 


The most controversial part of Mr. Buchanan’s paper is that in which he advocates a reduction in 
freeboard in ships where watertight steel hatch covers are fitted. 

In article 8 of the International Load Line Convention respecting load lines, 1930, which refers to 
Provisions for Special Types, is the first mention of subdivision in connexion with the assignment of 
freeboards to cargo ships. Up to that time freeboard had taken no account of the internal arrangements 
of a ship but only of her outward form, all openings in the latter being required to be closed so as to 
exclude water. 


Before the signing of the Convention it had been the practice of some countries which owned tankers, 
but which had no load line regulations, to load the vessels to draughts exceeding those corresponding to 
their freeboards determined by the Board of Trade Regulations of 1906. _ To bring these countries into 
participation in the convention it was necessary to give them some concession as regards tanker loading. 
Tt was thus that subdivision came into consideration in dealing with the freeboards of tankers. Now it 
is admissible that subdivision does play a part in the safety of such vessels ; it is even conceivable that if 
a compartment filled with heavy oil were bilged the vessel would actually rise in the water instead of 
sinking deeper. Another point in favour of the deeper loading of tankers is that the nature of the cargo 
is such that in an emergency it can readily be discharged without removing the hatch covers. In neither 
of these respects can an ordinary cargo vessel be considered to approach the tanker type, however 
watertight are her hatchcovers. ; 

Mr. Buchanan appears to be under the impression that the total deeper loading afforded to a tanker, 
or to a ship of special type, is made up of a number of small individual allowances for each of the special 
features provided. This is not the case, however, as most of these features are required because of the 
deeper loading allowed, and not vice versa. For example, because of the reduced height of platform it 
is necessary for a forecastle and a fore and aft gangway to be fitted for the protection of the crew, for a 
more effective protection of all openings to be afforded, and for open rails to be provided in order to clear 
the decks of the greater amount of water which will be shipped; such features were not considered 
excuses for reducing the freeboard. 


Mr. Buchanan, himself, admits this by approving in the penultimate paragraph of page 15 the 
quotation : “They” (ie., the Load Line Committee) * endorsed this opinion by practically stating that 
the question of protection of openings had nothing to do with the actual freeboard assigned, and they 
required all these questions to be dealt with, not in the terms of freeboard, but as a condition of the issue 
of a freeboard certificate.” 


All freeboard assignments are made on condition that the means of closing of all deck openings are 
efficient, the standard of efficiency being represented by the rules for wood hatches, and no reduction of 
freeboard can be contemplated if they provide a degree of efficiency greater than the standard. If the 
standard of efficiency is too low it should be raised, but that is no argument for a reduction in freeboard. 

Mr. Buchanan maintains that a large watertight hatchway affords more reserve buoyancy than a 
superstructure which has the openings in its end bulkheads closed by shifting boards in riveted channels. 
This is undoubtedly true, but the allowance for superstructures in freeboard computations is given, not 
because they afford reserve buoyancy, but because they protect the machinery openings, provide a higher 
working platform and protect the decks of the vessels from head and following seas. 

Having ventured to criticize the author in this important section of his paper, may 1 add my thanks 
to him for providing one of the most useful and exhaustive contributions which has yet been made to the 
transactions of the Staff Association. 


A. URWIN. 

The efficiency of the Wood Hatch Cover System has been questioned so often during the past ten 
years that we have become familiar with most of the pros and cons of this subject, nevertheless, 
Mr. Buchanan has succeeded in producing a most refreshing review of the subject and some new arguments. 
The only argument against the wood hatch cover that Mr. Buchanan appears to have omitted from his 
paper is that when you want to retain water in a ship—as in a deep tank—you must fit a steel water- 
tight cover, but for the purpose of keeping it out, wood covers may be used. 

The development of size of hatchway, which shows no signs of slowing down, makes the old method 
of protecting openings more unsuitable as time progresses. The essence of the weakness is the number 
of parts required, their dependence upon each other and the uncertainty of the materials except when 


~] 


new. The advantages of an all-steel construction having few parts and a standard of strength equal to 
that of the deck are beyond argument from a technical viewpoint, and the number of casualties traceable 
to failures of hatch coverings is sufficient reason for the encouragement of what is now a practical 
proposition. 

The drawbacks of the steel watertight cover system appears to be mainly the initial cost, and 
secondly, the possibility of delays in port to repair damage by grabs or other causes which may impair the 
nicety of fitting required. The second reason, however, may be more imaginary than real in many trades. 
Whether the encouragement to fit steel watertight hatches should take the form of slightly increased 
draft is, of course, a very debatable point, but as paragraph 109 of the 1932 Convention Freeboard 
Rules debars ships below 300 ft., and would exclude most self-trimming colliers, | believe Mr. Buchanan’s 
arguments are reasonable and would make for safer ships and lessen damage to cargoes. 


With regard to the bulging outwards of end coamings, | do not think this is as dangerous as it was, 
beeause, before a cover can drop, the bulge needs to be at least 2} ins., and modern coamings are better 
stiffened and stayed than they used to be. I congratulate Mr. Buchanan on the thorough manner in 
which he has dealt with this subject. 


D. GEMMELL. 


The author’s statement that steel watertight hatch covers are not considered to be absolutely care- 
free has caused me to think with some concern about the insulated steel hatches fitted on the weather 
decks of several recently constructed refrigerated ships. 

These hatches are jointed with rubber and greasy hemp, and the author suggests that with this type 
of hatch cover damage to cargo might not altogether be eliminated. It is also stated in the paper that 
with jointed steel hatch covers no tarpaulins are required. 


Would the author inform us whether it has been found that distortion of these covers takes place 
when the vessel is in a seaway and if leakage at the jointing has occurred thereby. This is a particularly 
important point where refrigerated cargoes are concerned, because there is not only the risk of damage to 
the eargo by water but there is the liability of the temperatures being affected through warm air being 
drawn in by pumping action. 

Surely, if there is any lability of leakage taking place at the joints of steel hatch covers, these 
should be covered by tarpaulins for the prevention of damage to the cargo by water. 


Murray. 

There are three divisions of this paper which merit particular attention: that dealing with the 
question of deeper loading when steel covers are fitted, that dealing with the objections to the statutory 
arrangements, and that descriptive of the various types of hatch covers. 

Concerning the question of deeper loading when steel hatch covers are fitted, at first sight it would 
appear that the anthor’s argument is sound; the advantages of a steel lid to the hatches are apparent, and 
the 1932 Convention Freeboard Rules undoubtedly make provision for this arrangement. But on 
further consideration it might be argued that it is hardly a wise policy to increase the factor of safety by 
fitting steel covers and then to reduce it to the status quo ante by increasing the draughts. Further, it 
must be kept in mind that the various subsidiary openings on a cargo ship—v entilators, companionways 
and the like—present an element of danger which does not exist in a tanker. However, the author has 
put forward an argument which would be difficult to controvert in its entirety. 

With regard to the objections which are assigned to the various parts of the statutory hatchways, it 
should be noted that no one of these is inherent in the arrangement itself, but rather due to the human 
element. It is apparent that a similar list of objections to steel covers could be compiled, and that the 
types evolved so far are far from perfect. 

An extract from a letter to Tue Tres follows, which gives the seaman’s point of view :— 

Sir,—Amid all the changing practices of present-day shipbuilding it does seem strange that 
the general desire to discover a type or design of invulnerable ship should have given such scant 
attention to the methods of securing the large cargo openings in the deck. 


8 


In the majority of sea disasters the evidence available has proved that casualties have 
been primarily due to the failure of the tarpaulin and wood hatch covers ; and as a master mariner 
actively engaged on the sea until early this year, I can testify to the continual source of anxiety 
that wooden hatch coverings are in practically every storm. 

All practical seamen will endorse Sir Joseph Isherwood’s views about the necessary substitu- 
tion of steel for wooden hatches. Unfortunately, what would seem to be lacking is the provision of 
an efficient steel hatch cover. A steel hatch cover to be successful must, in the first place, be of 
simple design and able to be operated by one, or at the most two, members of the crew quickly and 
efficiently; in addition it must be watertight. I have had the privilege on several occasions of being 
shipmates with steel covers, and only a month ago I was present al a demonstration of the latest type. 
These types all look, and are, in the ideal environment of. a shipbuilder’s yard impressive, but under 
actual working conditions they leave much to be desired. 

Unfortunately, the best brains of the shipbuilding industry cannot have been concentrated 
enough on this question, otherwise surely an archaic system that has for years been the traditional 
method of battening down hatchways would have been considerably improved upon and a type of 
steel hatch evolved that would lessen the risk to the lives of seamen, and at the same time prove 
acceptable to shipowners by reason of its cheapness and efficiency. 

This emphasises, what Mr. Buchanan mentions but does not stress, that the steel hatch covers at 
present available will not prove an immediate solution to the problem. 


It must be realized that the perfect steel hatch cover will be a great improvement on the present arrange- 
ment. That the authorities realize this is evident from the following letter which appeared in “The Times.” 
“For some years the Board of Trade and the classification societies have given close attention 
to the subject, and where effective steel hatches are fitted, they are passed by their surveyors. It 

is a policy of encouragement, not of compulsion. 

“The compulsory use of steel covers was considered by the Board of Trade Load Line 
Committee (1927-29), of which I was the chairman, but the evidence available at that time did 
not justify such action. No fewer than 36 of the 6% witnesses before the committee possessed 
long experience in handling ships of all types loaded with all kinds of cargoes. Their evidence 
disclosed wide differences of opinion about steel covers, probably because there was so little 
experience of them in actual use. 

“The International Load Line Conference of 1930 was faced with the same position, but 
there has been considerable experience of various types of steel hatches during the past six years, 
and the importance of the subject would warrant the authorities in considering whether the time 
has come for an impartial examination of the facts disclosed by the experience, to see if any useful 
action can now be taken.” 

In conclusion I would suggest that the author, with his unrivalled knowledge of this important 
subject, might be in a position to produce a cover which might combine the virtues of both the steel and 
the wood types of hatch covers. 


L. H. F. Younc. 

This paper is in one respect similar to the recent one on Steering Gear, inasmuch as the rod and 
chain gear was regarded with suspicion on account of the numerous components which went to make up 
the whole gear; so in this paper, the weakness of the usual type of hatch lies in the number of its 
components, and the efficacy of this type is therefore dependent on its general maintenance. 

The author on page 7 draws attention to the class of timber used for hatch covers. Although it 
should be the duty of the surveyor to see that a suitable timber is used, it would be a most difficult 
matter to lay down a rule, owing to the numerous varieties of soft woods available. 

As an example of the general strength of the usual type of hatch, a case might be quoted of a vessel 
which came under survey about 12 years ago. This was a flush deck vessel of about 5000 tons with 
three decks. She took a sea on to No. 1 hatch. The whole hatch, together with the surrounding deck, 
was set down about 8 ft. The second deck was set down somewhat less and the third deck less still. 
The upper and lower ‘tween deck pillars and the hold pillars were buckled in regular gradation ; but the 
whole of the hatch remained completely intact, also the ventilator coamings. This was a unique tribute 
to the Society’s Rules for hatchways and ventilators. 


BUCHANAN. 


I would like to add my quota of thanks to Mr. Buchanan for this interesting and instructive paper, 
in which he gives us details of the latest arrangements which have been provided for closing the 
hatchways. The descriptions of these ar rangements: and the photographs and drawings will prove of great 
use to his colleagues. There is no doubt that Mr. Buchanan is an advocate of steel hatch covers, or shall 
I say an adversary of the ordinary arrangement of wood covers and tarpaulins. 


Here, I think, we are presented with a problem which is very familiar, in other parts of the ship’s 

peli eer nt as well as hatchways. The present arrangement, if examined periodically and kept in 

easonable state of repair, has been proved efficient by its long and successful use, but the steel covers are 

an improvement, the only drawback being the ine reased cost. The author is of opinion that the saving 

in repair expenses more than balances this increased initial cost, but as an added incentive he has advocated 
an increase in draft for those vessels fitted with steel covers. 


He has made out a very good case for this increase, but if the advantages in upkeep costs, which are 
the principal items in which a shipowner is interested, are so much in favour of the steel cover , 1 do not 
see why this additional incentive is necessary. Again, the 1906 freeboard tables were based on a certain 
percentage of reserve buoyancy, and although this percentage is not given in the Convention regulations, 
I think it must be admitted the basis is the same. So that, prov ided all the vulnerable openings in the 
vessel are closed to a definite standard, the freeboard gives a certain measure of reserve buoyancy in the 
event of the vessel being bilged. 

While the fitting of steel hatch covers to the weather deck hatchways increases the standard of 
closing of these openings, it cannot affect the amount of reserve buoyancy required if the vessel is bilged 
in any other way. 

Let us suppose that the thickness of a steel hatch cover considered necessary is *30 in. If an owner 
increases the efficiency of the closing arrangements by making the plate °50 in., could he claim a further 

reduction in freeboard ? The answer is, of. course, No, because he has fitted a closing arrangement above 
the standard considered necessary. The same argument can be extended to the increase of efficie ney of 
the steel hatch cover of 30 in. over the standard of wood covers and tarpaulins considered necessary. 


The question of the freeboard of the tanker comes in an entirely different category, as the spacing of 
the bulkheads, the nature of the cargo and many other items, do not make it essential that such a large 
percentage of reserve buoyancy should be maintained. 


The author criticises the method of fitting cleats now adyocated by the Board of ‘Trade, namely, 
alternately facing forward and aft. It may be of interest that this has been the practice of at least one 
shipyard for many years. 

I intended to ask the author some questions concerning the insurance viewpoint of the wood versus 
steel hatch covers, but Mr. Thomson raised the question in ‘his contribution when the paper was read, so 
that Mr. Buchanan will probably give all the information when replying. In conclusion | would again 
like to thank the author for all the information which he has collected and passed on for our benefit. 


MACMILLAN. 


The question of reducing freeboard when watertight steel hatch covers are fitted is of especial 
interest, and may be regarded as one of primary importane e in this paper. As the author has stated, 
any additional capital expenditure involved in fitting steel covers is only to be justified in many 
commercial minds by increased earning capacity of the vessel so fitted, and he considers that a case can 
be made out for such by permitting deeper loading. On the basis of the 1982 Load Line Rules it would 
appear that this is not so, because paragraph 109 of these rules So to special steamer freeboards 
detinitely refers to * the degree of subdivision provided in the ship.” Now Mr. Buchanan states that the 
words quoted appear to have no bearing on this case, as freeboards are not dependent upon subdivision 
but upon the geometric form of the ship alone. This is true only when ships of any one type contem- 
plated by the rules are considered and I would suggest that, from a comparison between tabular steamer 
freeboards and tabular tanker freeboards, the higher degree of subdivision provided in the tanker has 
influenced these freeboards to some extent, and that this is cles arly implied in paragraph 109. 


10 


With regard to the higher degree of subdivision to be provided in the case of this hybrid ship, the 
proposition does not seem to be impossible as the author suggests. Taking the examples of the cargo 
vessel and tanker with dimensions as given, and the hybrid ship fitted with steel hatch covers and with 
3 ins. more draught than the cargo vessel, an inspection of the flooding and permissible length curves for 
these three vessels indicates that subdivision requirements would be fully met by the fitting of one 
additional watertight bulkhead oyer the number required by this Society’s rules, that is, seven bulkheads 
in all. As this means an average decrease of approximately 15 ft. in the length of hold compartments 
it does not seem to be wholly impracticable where the trading conditions do not demand the maximum 
length in these compartments. 


I agree with Mr. Buchanan that every encouragement should be given to the shipowner to produce 
a more seaworthy ship and that extra draught is often a good inducement. 


C. H. Stocks. 


We are indebted to Mr. Buchanan for this contribution to our transactions, in particular for the 
inclusion of a comprehensive selection of steel covers, detailed information of which is not generally 
available. Advocacy of steel covers is clearly the object of the paper, all else—history of the subject. 
pungent commentary on the wood covers and somewhat questionable criticism of — statutory 
authority and executive ability—is subservient to that issue. One cannot but observe painstaking effort 
to enumerate the shortcomings of wood covers and less concern to afford substantial proof of the merits 
of steel covers. The full statement of Courts of Inquiry and periodic revision of the rules scarcely 
support the author’s plea that the subject has not received proper attention, rather does he infer failure 
to appreciate the solution of the problem in steel covers. 


If the matter was simply a choice of materials then there could be no argument, but this is only one 
aspect ; conditions in service are severe and ease of maintenance is particularly important. Wood covers 
may be old fashioned and require frequent renewal, but they temporarily stand up to the customary 
rough usage and are easily replaceable at any time or place, a virtue particularly absent in the case of 
steel covers. 


Steel covers were introduced some 20 years ago, long enough to establish any particular virtue, but 
the fact remains that they have only been adopted to a limited extent, not to general practice but to 
particular cases. The quoted saving of £200 per annum per ship requires some ‘qualification and is not 
a representative figure, else it is remarkable that any other incentive is needed for their general adoption. 
I think the author might quote some extended experience, liability to damage in handling, maintenance 
costs and period before requiring renewal on account of corrosion, &e. 


Looking at the matter from the surveyor’s point of view, he has no qualms in recommending the 
renewal of a few wood covers or an odd tarpaulin; the cost on each occasion is small and the delay nil, 
but the condemning of a large steel cover, with special fittings, is a very different matter both on account 
of cost and delay, possibly to lead to undue postponement. In several of the designs for steel covers, 
one observes numerous “ bits and pieces,” brilliant conceptions but too gadgety to withstand port usage. 
These are points which appeal to an owner; my enquiries do not confirm that first cost is the excluding 
factor. One is impressed with the author’s criterion that the strength of covers should be equivalent to 
the adjacent deck, but it would be wrong to imply that all steel covers achieve this standard. On the 
contrary, the designer of steel covers is less concerned with that distinction than to obtain rock bottom 
scantlings so that the weight for handling is reduced to a minimum. Subdivision of steel covers to 
handy size multiplies the number of joints, a questionable gain. 


On the issue of strength, there is no apparent hindrance to an increase in thickness of wood coyers, 
if need exists, or they may be reinforced by slabbing. Wood wedges could be replaced by screw clamps. 
Some error is surely apparent in the suggested procedure for dealing with fires in cargo "tween decks. 
Surely the removal of hatches to insert hoses, defeats the purpose of turning the ventilators to leeward to 
ice access of air. If hatches are thus removed, is it material whether they are made of steel or 
wood ? 


11 


S. TowNsHEND (Gothenburg). 


Mr. Buchanan has presented his paper on Hatchways in such an excellent manner and phrased his 
comments and criticisms in so readable a style that he has converted, what otherwise might have been a 
rather dry subject, into a most absorbing one. 


Although, as the author states, it lacks abtruse calculations and theoretical observations, the subject 
of hatchways is of the very greatest importance and many clever brains are being directed towards it at 
the present time. The author leaves us in no doubt as to his own opinions on the inefficiency of the 
conventional wood hatch covers and shifting beams, and I am in complete agreement with his views. 
Much can be done by careful supervision and maintenance, and in times of stress, by careful handling 
of the ship, to ensure wood hatches being reasonably effective, but the master often cannot handle his 
ship at the dictates of discretion. The conventional arrangement of wood hatches is, without question, a 
vulnerable structure very much less in strength than the adjoining deck plating and beams and also less 
in strength than the adjoining wood deck in ships where a wood deck is permissible by the Rules. The 
damage which can be seen occasionally where decks have been set down by a heavy sea causes one to 
wonder what would have happened to the ship if the sea had come on to the hatchways instead 
of the deck. 


A case recently occurred of a vessel which suffered very severe damage during a gale. A sea, which 
from the accounts of those on board and from a study of the damage sustained, must have been of 
phenomenal height, came over the port side forward of midships and swept diagonally aft and across the 
ship to the starboard side. The whole of the upper deck forward of the saloon house was set down, the 
fore mast and the derrick lying housed against it were bent, the saloon house between Nos, 2 and 3 hatches 
was fractured and battered out of shape and the navigation bridge on top thereof was completely destroyed. 
The port bulwark amidships was laid flat on deck and the starboard bulwark was bulged outboard. ‘Two 
boats on the starboard side on top of the deckhouse aft of No. 3 hatch were washed away. Nos. 2 and 3 
hatchways were staved in and a great volume of water poured down on to the 2nd deck. The vessel, 
which was of the small shelter deck type with tonnage opening aft and without overboard scuppers in the 
2nd deck. took at once a very heavy list and lay with the starboard side of the shelter deck so immersed in the 
sea, that water commenced running into the engine room oyer the sill of the door in the casing in 
the passageway on the starboard side. 


In accordance with a common practice the tarpaulins had not been fitted to the 2nd deck hatches, 
The water lying on the 2nd deck gradually filtered past the wood hatch covers into the holds, where it 
was dealt with by the bilge pumps and slowly the ship was righted. If the law in regard to the 2nd deck 
hatchways had been complied with there would have been no way of dealing with the water in the “tween 
decks and the ship would probably have foundered. 


The foregoing case has been cited at some length in order to show :— 
1. That the damage done by one sea to the steel structure, though very severe, did not imperil 
the ship. 
2. That the same sea broached two of the hatchways and placed the vessel in a position of 
the gravest danger. 


It is suggested that the internal arrangements of the ship should always be designed so that in the 
eyent of the weather deck hatchways being broached, water entering the ship can readily find its way 
into the holds and to the bilge suctions, but in vessels of the type just considered this seems difficult to 
obtain in practice. 


Respecting tonnage hatches the author states that as cleats are not permitted tarpaulins are not 
intended to be used. In practice tarpaulins are always fitted and when the tonnage hatch is built with 
semi-circular ends it is a very simple matter to arrange a means for securing the tarpaulins which is much 
more efficient than cleats and wedges. 


Having regard to the acknowledged vulnerability of wood hatches, it is not surprising that there are 
so many patent steel hatch covers and a still greater number of steel covers which are not patented. 
There is one important point to bear in mind in designing steel covers. The edge of the cover should 
not be too stiff or rigid, or otherwise there will be difficulty in securing a weathertight joint at the 


12 


packing, especially if the vessel is trading in cold climates. It is better to have a flexible edge with closely 
spaced bolts of reduced size than a stiff frame with widely spaced bolts. Hatch covers designed on this 
principle, which is the same as usually applied to oil tank and deep tank hatches, have proved very 
. Satisfactory. 

A reduction in freeboard in a vessel fitted with steel hatch covers may provide attractive compensa- 
tion to the owner for the increased cost, but it is scarcely scientific, because, as the author points out, 
some increased strengthening is required to the strength deck, and in the case of existing ships this is 
scarcely practicable. As the Insurance Societies would be the principal beneficiaries of the increased 
safety conferred by steel hatches it is suggested that they should return most of the legacy to the 
shipowner by reducing the insurance premiums. It is noted that the late Sir Joseph Isherwood has also 
made a proposal on these lines in a letter to ‘The Times.” 

The author says on page 17 that the connection of the hatchway coaming to the deck plating is 
considered an item of primary structural importance, therefore electrodes classified in this category must 
be used. As the welded hatch coaming connection to the deck must of necessity be continuous on one 
side and at least intermittent on the other, it is very much superior to the riveted connection and I 
should have thought that the electrodes need only comply with Section 4, Clauses 1 to 6, of the Society’s 
Regulations. Connections made with such electrodes are considered suitable for withstanding the heavy 
test pressures of double bottoms under test, and I should have thought them quite suitable for hatch 
coamings. 

Fitting steel hatches in the ’tween decks of shelter deck ships seems rather an extravagant method 
of fire restriction, and I doubt very much if such a method could be made effective. The practice with 
many Swedish shipowners is to fit steel fire bulkheads in the "tween decks, the openings in which are 
closed with portable steel plates secured by hook bolts. 


R. 8. Jonson (Hamburg). 

Several enquiries held into the cause of loss of ships have of recent years attributed the disaster to 
failure of the hatch covers, and the prominence thus given to the subject has resulted in many new methods 
for closing hatchways being proposed. Mr. Buchanan’s paper is therefore of great interest, and he is to 
be congratulated on the form of its presentation. 

When one considers the long period during which the wood cover system has been in use, it is hardly 
possible to write it off as wholly inefficient. It is a system easily handled, can be repaired on board and 
when, like many other items of ship fittings, properly maintained serves its purpose. 

The controversy is mainly one of wood or steel and undoubtly the latter material has advantages over 
the former, particularly where the human element is concerned, and rightly as referred to by the author, 
in cases of fire. For small hatchways, to follow the tanker steel cover arrangement is desirable, but this 
is not possible for the large openings now generally necessary to the purpose of the modern ship. With deep 
sea ships there is not so much danger as in the small coastal type particularly the self trimmers where the 
coamings are close to and about the same height as the bulwarks, in which case the unprotected covers 
must take much punishment from the sea, 

The real trouble is apparently not so much the smashing in of the covers, but their fitting so badly 
as to become dislodged, and here steel covers with some fixing arrangement would be a remedy. It is not 
seen that the design of steel covers need be concentrated on the omission of webs, indeed these perform a 
useful function in supporting the coamings, and their retention is desirable particularly for long coamings, 
and covers designed on the lines of the illustrations, Figs. 14 and 15 in the paper, whether of wood or 
steel, appear to obviate many objections to the present system whilst still retaining its advantages. 

The author’s argument favouring the granting of a reduction of freeboard as an inducement to owners 
to improve a ships fitting considered vulnerable is not followed. If necessary, it should be a requirement, 
but apart from this, when a good practical alternative to the present system is forthcoming, doubtless it 
will be adopted. The author’s suggestion to divide the openings is worthy of consideration and would be 
no inconyenience in some special services. 

The remarks in the paper relating to wood wedges are very much to the point, when these become 
loose in bad weather it is often a hazardous task to secure them again. Damage to tarpaulins due to the 
carriage of deck cargo is not unusual and in all such cases the hatchways should he completely protected 
with suitable dunnage before the deck cargo is shipped. 


13 


A. W. Jackson (Liverpool). 

Mr. Buchanan is to be congratulated and thanked for his monumental work on “ Hatchways,” a 
subject very much under discussion at the present time. It is perfectly obvious that the whole crux of 
the situation is cost. Steel hatch covers are a more expensive first cost to a shipowner than wood hatch 
coyers, and purely from the matter of business the cheaper article is fitted as long as it passes certain 
requirements. 

The only way to prevent loss of life at sea through hatches being broached due to heavy weather is 
to bring in legislation making it compulsory for steel hatch covers of a certain minimum standard 
strength to be fitted to all exposed hatches. Another point that might bear consideration is the fact. that 
wood hatch covers are not always “stove in,” but the pounding of the waves is sufficient to compress the 
sides of the ship and * blow the hatches off.” 

The author has given us a wealth of illustration in the paper, but he has omitted to show the 
doubling plates at the ends of the hatch beams in Fig. 1. In my own experience I can bear out the 
author’s statement given on page 7 regarding the omission of the intermediate hatch beams. In the 
particular case I had under No. 3 survey, the intermediate hatch beams were not in the ship at all, but 
up in the store, like the Dutchman’s anchor. It might interest the author to know that the British 
Tanker Co., Ld., are fitting the 12 in. coamings on their new ships, and have stanchions and chains 
round each hatch. 

In Appendix 1, case C, the author quotes the case of a vessel where water entered the stokehold and 
engine room through the bunkers, the tarpaulins of the port bunker hatch on the bridge deck having 
been torn and washed off by the heavy seas. 

It will have come under the notice of a number of colleagues that, generally speaking, the tarpaulin 
over the bunker hatch is one of the large cargo hatchway tarpaulins cut down, and not in the first blush 
of youth. Also the wood hatches themselves are a collection similarly treated from discarded cargo 
hatches. 


KE. G. Hsernqvisr (Gothenburg). 

I congratulate Mr. Buchanan on his excellent paper and for the very complete information he has 
given in regard to the closing of deck openings. The regulations only require the end coamings of hatches 
to be stiffened and supported when they are aboye a certain size and are not protected by an adjoining 
structure. One can infer from this that damage to the end coamings in general is to be expected only 
from seas coming on board. In practice the end coamings are often deformed by the loading or unloading 
of a heavy piece of cargo or by the discharging grabs in the case of * self-trimming ” coal vessels. In my 
opinion the end coamings of hatchways should be stiffened and supported the same as the side coamings 
irrespective of any local protection afforded by neighbouring deckhouses. In some cases I haye seen end 
coamings so deformed that when the fore and afters have been dropped in position there has remained 
only about 4 in. of bearing surface. 

There appears to be some doubt as to what is meant by the words * bearing surface.” The amount 
of bearing surface required by the regulations is of course always provided, but the shrinkage of the covers 
or the slight deformation of the hatch may reduce the effective bearing surface very considerably. I haye 
observed a case where the bearing surface provided at each end of a fore and after has amounted to 4 ins. 
but the deformation of the hatch has been such that if the fore and after had been shifted hard aft, the 
bearing surface at the fore end would have been reduced to 14 ins. 

The same remarks apply to the wood coyers and | should therefore like to ask the author if he can 
say exactly what “bearing surface” is intended to mean. In practice some clearance is essential, but, 
how much ? Sockets for hatch beams or hatch fore and afters, if made of cast steel are very rarely broken 
but if made of cast iron they are often damaged. I agree with the author’s remarks in regard to the 
quality of wood hatch covers. Some degree of safeguard against undesirable qualities of wood being 
used could be obtained by specifying a minimum weight for the timber on the lines of the Society's 
Yacht Rules. 

Another point in regard to wood covers is that damaged covers should, not be repaired by pieces 
scarphed or nailed in place. The cover should be repaired by adding a strip of wood for its ful/ length, 
efficiently through-bolted to the old piece. Where it is possible to do so, very small differences in 
the spacings of hatch webs at the various hatches should be avoided. There is a natural tendency for 


14 


covers to become mixed, and if it is possible to put the wrong covers on a hatchway the perversity of human 
nature is sure to see that it is done and the same human quality will leave it alone even when found out. 
It should not be difficult to have the hatch webs so arranged that the covers are either exactly the same 
length or so different in length that there can be no doubt as to which is their correct position. 


I do not think the reduced freeboard of tankers can’be ascribed solely to the better protection of the 
deck openings. It is much more due to the small size of the hatches and to the very efficient sub-division 
of the hull structure. The tanker would be just as safe if the usual hatches were fitted with wood covers 
and tarpaulins. 


R. B. SHepHEARD (Hamburg). 


This is a most valuable paper, packed with practical information. The author has performed a real 
service by his thorough treatment of a subject of literally vital importance to those that go down to the 
sea in ships. The reports of Board of Trade Inquiries provide tragic evidence of the vulnerability of the 
orthodox hatchway arrangement. It is surprising to note that several of these losses were due to stoving 
in of bunker hatches, situated on the bridge or the shelter deck amidships and presumably of small 
dimensions. This emphasises the importance of all weather deck hatches, irrespective of their position 
or size. 

It isconsidered that wood hatch covers are rendered much more efficient by the fitting of steel bands 
round their ends as described on page 21 of the paper. Such protection should be of especial value for 
ships engaged on short voyages, including self trimmers, in which the wear and tear on the hatch covers 
is particularly heavy, and which experience has shown are very liable to heavy weather damage. Wood 
fore and afters being at present required to be steel shod, the extension of this requirement to wood covers 
is a logical step, inflicting in the long run no hardship on the shipowner in view of the greatly increased 
life of the covers. 

Deck hands should, however, be warned before handling such covers. Owing to the steel to steel 
surfaces between the rest angles and the covers, the latter slide very easily when being shipped, and 
a case arose recently in which two men when swinging such a cover into place, being unable to let go of 
the hand grips quickly enough, were swept off their feet and lost their lives by falling to the hold below. 

While hatch webs have to be provided with locking arrangements, no such general requirement 
exists for hatch covers, except that provided by the tarpaulins. The author gives particulars of several 
arrangements of wood and steel section covers in which the advantage of positive locking is provided. 
Lashings, as the author states, are often unpopular owing to the damage they do to the tarpaulins. Rope 
lashings are less destructive than wire and can be set up tighter unless a good number of stretching 
screws are fitted to the latter. Locking bars fitted across each set of covers provide more definite fixity, 
but are liable to damage the tarpaulins by tearing when fitted at specially exposed hatches, or by the 
formation of lines of rust at their edges. 

Steel covers undoubtedly greatly increase the safety of hatches and their development is therefore 
strongly to be advocated. That a great deal of thought has already been devoted to this matter is 
indicated by the variety of types described by the author. It is, however, felt that some of these types 
are subject to practical objections and as stated on page 2 of the paper, their fitting is not “absolutely 
care-free.” For example, those shown in Figs. 28, 36 and 38 are not considered suitable when deck 
cargoes are carried. The stowage of some types in port is awkward, involving loss of hatch space as in 
Figs. 40 and 44, or of unwieldy areas acting as sails, Fig. 30. 

Again, the closing and maintaining watertight of an opening 30 ft. by 20 ft. or more is a very 
different proposition from that for small covers such as fitted in tankers. The tightness may be adversely 
affected by slight deformation at the bearing surfaces or by working at sea. The experience of men who 
have been shipmates with such covers for several years—not only when these have been newly fitted— 
would be interesting. 

With some of the arrangements illustrated some leakage would probably be fairly common and 
claims for cargo damage not infrequent. Such objections will no doubt be overcome in the course of 
further development, but a great deal more experience with large steel covers is thought necessary before 
any concession in freeboard such as that mentioned by the author could be considered ; nor will such an 
inducement be necessary, if the economy reported by the superintendent of a large line of passenger and 
cargo ships as a result of fitting steel covers, mentioned on page 20, is found to be general. 


a) 


J. Housvon (Leith). 


The fact that the more or less universal method of closing the hatchway openings in the weather 
decks of vessels with wood covers and tarpaulins is still the prevailing arrangement, and that this practice 
has continued for so many years, is proof of the difficulty which has been experienced in finding a 
better method, 

To the lay mind particularly, it must seem curious that this very vulner rable part of a vessel is 
still being closed with wood covers and canyas, held in place by lashings, especially when one remembers 
that, of late years, the sizes of hatchways in cargo vessels have been very considerably increased. There 
are many arguments against adopting this or that method, and we have to thank Mr. Buchanan for 
bringing before us, in a condensed form, particulars of some of the more modern methods, which are 
now being tried out. 

I do not think that the naval architect can yet write “ finis” to this very important subject. As long 
as the effect of heavy seas coming on board a vessel remains an incalculable element, inventors will still 
come forward with ideas to combat the danger. There is a wide difference of opinion about steel covers, 
and if a vote were taken amongst nautical men on steel yersus wood covers as the "y now exist, the latter 
would win, in spite of the knowledge of the increased safety, that the steel cover gives. To the sailor it 
is not all a question of safety. One can safely say that every type of steel cover that has been devised, 
is probably strong enough to withstand the heaviest sea likely to be experienced on deck. Convenience 
in battening and unbattening will appeal to the sailor, and serious trouble has been experienced in the 
use of steel covers by the warping and twisting of hatch coamings, sufficient in some instances to 
necessitate the ripping open of the covers by ac etylene burners. Simplic ity of design is most important, 
but economy in construction and operation must go along with improved designs, otherwise there is small 
hope of new ideas being taken up. 

It will be generally accepted, however, that wood covers, when properly fitted and supported by the 
requisite number of hatch beams, are amply strong for their job, when maintained in good condition. 
It is a commonplace sight to see wood hatch covers being used for other purposes than ‘those intended, 
when discharging operations are in hand. 

The present-day practice of fitting mild steel bands, either open or with closed ends, to the ends of 
wood hatches makes a vast improvement, and adds very materially to the life of them. It is a matter of 
wonder that this simple invention was not taken up years ago. 

In the course of enquiries into the foundering of vessels, one often reads that “the tarpaulins were 


ripped.” I have never yet read where or how the t tarpaulins ripped, but it is fairly safe to say that it was 
along the seams. W hy ? The great majority of tarpaulins are machine sewn, with a running stitch, 


about } in. from the selvedge edge. This selvedge edge curls up, and when struck by a heavy sea, the 
stitching, probably weaker than the canvas—if not actually rotten—gives way, and the whole seam rips 
from end to end. 

Now if, instead of the stitching being done as a running seam, it were carried out zig-zag over the 
selvedge edges, the seams would be very much stronger. This is what I mean :— 


16 


The cost might be prohibitive, as it would mean hand sewing against machine stitching, but would 
it not be worth while? I know one shipowning firm which employs a sailmaker to make all their 
tarpaulins by hand. I have yet to hear of one of their tarpaulins ripping along the seam. 


REPLY BY THE AUTHOR. 

The author wishes to thank those members of the Association for their valuable contributions and 
opinions. Much that has been written does not call for reply, but an endeavour will be made to answer 
some of the points raised. 

It is significant that many of the contributions record that the wood and tarpaulin type of hatch 
covering stands in need of improvement. Criticism, from actual working experience, of the efficiency or 
otherwise of the watertight steel hatch cover is conspicuous by its absence, and while it would be too 
much to conclude that because of this absence, this type of cover is proving to be a success, nevertheless 
one’s thoughts are in that direction. The fitting of steel hatch covers continues to be a feature in new 
ships, and new designs are still being brought into the market. 

As was expected, the point which created most discussion was the author’s suggestion that a 
reduction in freeboard might be given to vessels fitted with steel watertight hatch covers, the common 
objection being based on the fact that cargo vessels are not sub-divided to the same extent as tankers. 

Adequate protection for hatchway openings is now a requirement for freeboard assignment, and any 
departure from the orthodox method of covering must have the approval of the authorities. It must be 
concluded therefore that the proposed type of cover will be strong enough and sufficiently watertight to 
prevent water from entering the holds, the other features, mobility, stowage, etc., being more an Owner's 
concern. The author does not suggest that a certain amount of care and maintenance is not required 
with steel covers, such as keeping the hemp or rubber jointings in good condition, but the most that 
could arise from a defect in steel covers would be nothing more than a trickle of water into the hold. 
Further, it is difficult to visualise any of the watertight steel covers described in the paper being floated 
off by a sea or even displaced. 

The Load Line Committee, in considering the question of a reduction in freeboard for tankers, 
stated “our main ground for accepting the principle is the efficient protection provided for openings in 
the weather decks by means of steel watertight covers.” Paragraph 109 refers to steamers possessing 
constructional features similar to those of a tanker, which afford extra invulnerability against the sea. 
The author’s dictionary defines “invulnerable” as * not capable of being wounded.” It is thought that 
steel covers satisfy this requirement better than closely spaced bulkheads which, after all, only become 
effective after the vessel has been wounded. 

It is interesting to quote what some prominent men have been saying recently with regard to the 
covering of hatchways. Sir Charles J. O. Sanders, in a letter to “The Times,”’ December, 1936, 
“The compulsory use of steel covers was considered by the Board of Trade Load Line Committee 
(1927-29). . . . There has been considerable experience of various types of steel hatches during the past 
six years, and the importance of the subject would warrant the authorities in considering whether the 
time has come for an impartial examination of the facts disclosed hy the experience, to see if any useful 
action can now be taken.” 

Doctor J. Montgomerie, on “Safety at Sea.” September, 1936. 

“Tt does seem that the time has come when more serious attention should be given to the 
various proposals, such as the adoption of steel covers, which have been made to obtain an increased 
measure of protection for these openings.” 

The late Sir Joseph W. Isherwood. Letter to * The Times,” November, 1936. 

“ Apart from the liability for wooden hatchway covers to be stove in, there is an equally grave 
danger of their being * floated off’ the hatchway when heavy seas wash over the ship, and the vessel 
and the lives of those on board are gravely imperilled ; many ships having been lost as a result.” 

Also in 1928-29 Mr. L. C. Burrill,* in order to study the seaworthiness of the collier types, made 
twenty-six voyages in different type colliers in the North Sea, English Channel, Bristol Channel, to the 
Bay of Biscay, and once across to Canada. It is significant to note that one of his conclusions was :— 

“Hatch Closing ARRANGEMENTS.—The only real solution to this very vital problem will 
be the introduction of some form of steel hatch covers for this type of vessel.” 


“Trans. I.N.A., Vol. LXXIII., p. 85. 


17 


[am more than delighted to have Mr. Watt’s contribution, and also his hope that the time is not far 
distant when steel covers will become the usual thing. He thinks that I have flogged the wood cover 
arrangement too severely ; but Ido not agree. Mr. Watt asks me if I can point to a defective arrangement 
being approved by the Board of Trade, and states that I gave away my case by saying * it is not contended 
that the strength or arrangement of the system is deficient or unsatisfactory.” However, he conyeniently 
omits the five following words * when the vessel is new” which qualifies my statement. 

It is easy to believe that neither of the two gentlemen with 40 and 47 years’ experience respectively, 
at sea, had ever seen a hatch stove in. On the lower half of page II, I made the same statement that no 
one has eyer seen a hatch being broken in by the force of the seas. The term “stove in” meaning simply 
that water has entered the hatchway. It is synonymous I think, to the message sometimes received that 
a vessel has lost her rudder. This does not always mean that her rudder has dropped off, but that she has 
lost the use of her rudder. 

Mr. Watt alleges that I support the statement that when end coamings are unstiffened they are 
frequently set in. My statement is that they are sometimes bulged outwards, an entirely different state 
of affairs. Other speakers have alluded to this possibility. 

Mr. Watt asks if I would suggest the fitting of a fore-and-aft gangway in a cargo ship. I thought 
I had made it clear that the only feature I was considering in the freeboard reduction question was, the 
fitting of steel watertight hatch covers. At any rate if a fore-and-aft gangway is not already fitted (some 
vessels with short wells do have gangways) then lifelines, according to rule 26, must be fitted ; lifelines 
being considered the alternative to fore-and-aft gangways in a cargo ship. 

Mr. Watt is indeed our Court of Inquiry expert, and knows more about how the findings are arrived 
at than any one of us. It is therefore a bit of a shock to our faith in these Courts to hear that the findings 
should always be taken with a grain of salt and that they do not always arrive at the truth. 

However, it would appear that we do agree regarding the difficulty which can be experienced in 
trying to re-batten a hatchway, as evidenced by the testimony of the captain in the witness box explaining 
the loss of 200 battening wedges. Iam much indebted to Mr. Watt for his final paragraph. 

Mr. Thomson entirely disagrees with me and ventures to suggest that modern methods of closing 
hatchways leave little to be desired. 1 can only repeat that the methods employed to-day are anything 
but modern. The scantlings and arrangements as prescribed in the Rules are sufficient and efficient, but 
the trouble is that the wood and canvas items are not so durable as the steel items. This would seem to 
be the general consensus of opinion. Prior, I think, to 1924, surveyors in examining the decks of ships 
at intermediate periods between special surveys, only made a superficial examination of the decks. After 
that date they were required to report specially on the condition of the hatchways, covers, etc., and all 
deck openings. Now, since the Convention Regulations have come into force, an Annual Freeboard 
Survey according to statute, must be held. Eyen now, as Mr. Blocksidge says, hundreds of wood covers, 
and dozens of cleats have to be renewed. Shipowners realise that the wood and canvas are not very 
durable and accordingly keep a supply of wood on board to make new covers, and usually carry spare 
tarpaulins. A superintendent who has made a very careful analysis of the subject, finds that he has to 
supply a new tarpaulin every 6} months to each hatchway of his ships. 

Mr. Thomson has reduced my figure of 13 per cent of the losses of British ships reported due to 
hatch failure, to an actual figure of 2 per annum. Surely even this figure is ample justification for 
giving the subject serious consideration. If a motor car manufacturer had convincing proof that the 
cause of 13 per cent of the accidents which his particular model sustained was due to the way in which he 
had designed some part of it, I feel confident in saying that he would very soon re-design that part. 

The figure of 13 per cent had been obtained after an investigation had been made of losses prior to 
1915, and Mr. Thomson thinks that with the increased requirements now in force the figure will be rather 
less. One must agree with this statement, and the natural deduction then would be a reduction in the 
figure 2 to something negligible. However, with regard to two types only, tramp coasters and colliers. 
I quote the following, from three different sources : 

“Eleven vessels of the tramp coasting class foundered in the four years, January, 1921 to 
to January, 1925.” 

* Fourteen vessels (coal carriers) foundered between September, 1921 and August, 1925.” 

* During the period 1922 to 1925 no fewer than forty-five vessels carrying coal cargoes were lost. 
Ina large number of cases it appears that the vital factor isthe efficiency of the hatch closing appliances.” 


18 


The number of cases on my list of inquiries is 23, over a period of 18 years, about 1°3 per year, and 
these-are only the cases in which an inquiry has been held. Possibly it is not generally known that an 
inquiry is not held into every lost vessel, but only when any useful purpose would be served or when any 
information has been received of some wilful act of neglect or other circumstances suggesting an 
investigation. The number of inquiries held is about one to every ten vessels lost from all causes. 


Mr. Thomson takes me to task over insurance rates. I did intend including a paragraph on this 
side of the subject. However, Mr. Townshend makes a very feasible suggestion that insurance rates might 
be reduced if steel hatch covers are fitted. 

Mr. Blocksidge points out how an opening into a poop space must have the wood covers fitted into 
riveted channels, whilst the wood covers protecting a much more vital opening need only lie on angle bars 
and be held down with canvas covers. It is assumed, of course, that the tarpaulins will hold down the 
wood covers. During my voyage to New York we experienced fairly rough weather and I naturally kept 
observation on the hatchways. The tarpaulins on one hatchway ballooned to a height in the centre 
of 30 ins. and this continued for eight days on end. It is therefore not surprising to hear that tarpaulins 
have to be renewed so frequently when they are subjected to so much flapping about for long periods. 


As an acknowledged authority on timber, I am glad to have Mr. Blocksidge’s corrections in regard 
to the names and locations of the wood for the making of hatch covers. I am also very glad to have his 
authentic information showing how, even now with the annual freeboard surveys, so many renewals of 
covers and cleats are required. 

Mr. Bryden refers me to the rules for the determination of freeboard for shelter deck ships. These 
do not contain de/ailed statutory regulations and I presume that Mr. Bryden has overlooked the word- 
“detailed.” I was of the same opinion as he, regarding the necessity for lashings but the Convention 
Rules do not state that these are to be fitted. I have never had experience of such a long hatchway as 
Mr. Bryden cites, but I have often wondered if the tarpaulins were always in one piece. The pulling and 
stretching of such a large piece of canvas into its proper position must be a feat. 


Mr. Bryden states that up to 1930 freeboard had taken no account of subdivision. I am not aware 
that it is a factor even now. There is nothing in the freeboard rules specifying number nor spacing of 
bulkheads in a ship, and I doubt whether a tanker would be penalised if the owner decided to make his 
tanks 50 per cent longer than the normal length with adequate stiffening on the end bulkheads. 
An ordinary cargo ship can have a lesser number of bulkheads than required by the Classification Rules 
if the exigencies of its service demand it. A suitable notation is made in the register book pointing out 
the omission, but there is never any increase made in the freeboard on this account. 


I am aware that the increment in draught cannot be made up in small pieces, and also that a tanker 
must possess all the essential features before deeper, loading can be permitted. However, I think the idea 
was first conceived because existing ships did possess these features and some did load much deeper than 
normal. It is also very significant that before an existing ship or, in fact, a new ship can get the deeper 
loading, the large hatchway to the forward or dry hold must also be closed with watertight steel covers. 
Some of the contributors have inferred that comparison cannot be made with the small tanker hatchways. 
This is true. but while the hatchway to the forward hold in a tanker is not as large as the hatchway in the 
general cargo ship, it is considerably larger than the hatchway to the oil tanks. It is also in a position to 
receive the worst punishment from seas and ] am not aware that these hatchway coverings have been found 
to be inefficient. 

I appreciate Mr. Urwin’s comparison to the deep tank covers. The requirement that these tanks 
must have steel covers efficiently bolted around their edges is for the prevention of damage to other cargo 
in the ‘tween decks. The wood and tarpaulin arrangement is for the protection of the ship and 
those on board. 

It is true that when covers are fitting properly, the end coamings must bulge outwards 23 ins. before 
the wood covers can fall through, but I am sure Mr. Urwin has condemned many coyers because of their 
shortness, either through shrinkage or other reasons. In some cases } in. would be sufficient for the 
coamings to be bulged outwards. 

Mr. Gemmell’s concern for the absolute airtightness of the steel cover is well founded. With 
refrigerated cargoes in the upper “tween decks, this condition is essential. I have not heard that steel 
covers distort in a seaway. The possibility is rather the reverse, that is, if the steel covers are made too 


1) 


rigid, when the vessel is in a seaway, pitching, rolling and twisting, the coamings might distort, causing 
the diagonal corners of the covers to rise off their seatings. A flexible edge with closely spaced bolts 
would seem to be the ideal arrangement. This is also suggested by Mr. Townshend for vessels trading 
in cold countries. 

My observation that watertight steel covers could not be considered absolutely care-free, referred to the 
obvious necessity for periodic examination of the rubber or hemp packings at the joints. In the case of 
insulated covers, [ would think that the examination of the jointing material should be made more 
frequent than in the case of ordinary cargo. 

Mr. Murray, in the question of deeper loading, considers it hardly a wise policy to increase the factor 
of safety by fitting steel hatch covers and then reduce it by increasing the draught of the ship. To me 
this comparison is barely feasible; an increase in draught of 3 ins. would scarcely be noticed in a 
100 ft. ship. The added danger to ventilators, companionways, etc., when 28 ft. of erections is added to 
get the legitimate increase in draught, is not considered. 

The extract of the letter to * The Times,” evidently written by a ship's master, is indeed interesting. 
This gentleman goes much further than I when he states that the majority of sea disasters are primarily 
due to the tarpaulin and wood hatch covers. The quotation of the second letter to “The Times” is also 
welcome, coming as it does from the pen of the Chairman of the Load Line Committee (1927-29). 
I entirely agree with his contention that an impartial examination of the facts disclosed by the experience 
during the last six years of the use of steel hatch covers is worthy of consideration by the authorities. 

The example given by Mr. Young of a complete hatchway with the surrounding deck being set 
down by a sea but the hatchway itself remaining intact is good proof that the strength of the wood cover 
is adequate. 

Mr. Buchanan wonders why an increase of draught, as an incentive, is necessary when it is also 
stated that a considerable economy is effected by the fitting of steel hatch covers. The average ship 
owner, being of a very conservative nature, would not risk incurring the expense of fitting steel hatch 
covers, Whereas byan increase in draught he would know exactly what he was going to get in the form of 
extra deadweight. 

I think Mr. Buchanan must have had flooding calculations in mind when he says “the freeboard 
gives a certain measure of reserve buoyancy in the event of the vessel being bilged.” Mr. Watt states 
that reserve of buoyancy is not the criterion but height of platform. At any rate, I don’t think that the 
Convention Regulations contemplates freeboard in the light of a compartment being bilged. As stated 
before, a main bulkhead of a ship can be omitted, in which case there would be little reserve buoyancy if 
the compartment were bilged. 

I appreciate Mr. Buchanan’s comparison of thickness of steel covers with a further reduction of 
freeboard. However, what I tried to point out was that the wood and tarpaulin arrangement when the 
vessel is new is sufficient, but the efficiency does not last for any appreciable length of time. 


It is admitted that the close spacing of bulkheads in a tanker did have some influence in the 
consideration of reduced freeboard, yet there is nothing in the regulations defining lengths of tanks. 
Mr. Macmillan has examined the case of the 400 foot ship with three inches more draught, and finds 
that one extra bulkhead would fully meet the subdivision requirements. This would seem to confirm my 
opinion that the “degree of subdivision” requirement is overstressed. ‘The average length of a tank in 
an oil carrier is about 32 feet. There are tankers sailing now with tanks 40 feet long and I feel sure 
there was no penalty on their freeboards. 

Mr. Stocks informs us that steel hatch covers have only been adopted in particular cases. ‘The types 
shown in Figs. 24, 26, 32 and 34 are now on passenger and cargo ships. Fig. 26 is also the type used 
on the weather deck of a ship carrying refrigerated cargoes in the upper “tween decks. Fig. 27, is a type 
on self-trimming colliers. Fig. 30 as fitted on ore and coal carriers. The remainder of the covers shown 
are for general cargo ships. The only types of ships of which I have no knowledge that watertight. steel 
coyers have been tried on the hatchways, are cross channel steamers and trawlers. 

Mr. Stocks wants some qualification for the reported saving of £200, per annum when steel coyers 
are fitted. A superintendent to another shipping company has informed me, as before stated, that a new 
tarpaulin is required to each hatchway every six and three-quarter months. 'Tarpaulins at 3s. per square 


20 


yard and five hatchways at 36 ft. x 24 ft., allowing 18 ins. overhang, would represent about £150. A 
modest allowance of ten wood covers per hatch per year at 22s. 6d. each would cost about £56—Total 
£206 without considering wedges, battening irons, cleats, ete. 


It is surprising to hear that a surveyor would have qualms in recommending the renewal of a large 
steel hatch cover. Does one have qualms in recommending the renewal of eight or nine deck plates if 
wasted or thin? At any rate it is not seen why a steel hatch cover should require to be renewed any 
sooner than the deck plating between the hatchways which can be -30 in. in thickness. The plating of 
steel hatch covers is rarely less than -28 in. It is thought that the majority of steel covers would be more 
accessible for cleaning and painting than the underside of decks and consequently last longer. 


Within the last few weeks I have seen-a ship, built and fitted in 1920 with the type of cover as 
shown in Fig. 30. The superintendent informed me that no repairs had been found necessary to any of 
the covers beyond some renewals of the bolts and nuts of the fastenings ; most surprising was the infor- 
mation that during the 17 years the packings had only been renewed. twice. It was also obvious that 
there had been a considerable economy effected. 


On the issue of strength there is no need to increase the thickness of the wood covers. Wood twice 
as thick would warp, shrink, split and become rounded on the ends just as easily. Wood covers, as 
Stated in the paper, when new are amply strong and in fact are twice as strong as the hatch wel beams 
Which support them. 


There is no error in the Suggested procedure for dealing with fires in the ‘tween decks. The criticism 
1s not understood but there is no indication in the paper that if steel covers are fitted they should be 
removed to deal with the fire. 


Mr. Townshend is in complete agreement with my views on the conventional hatch cover arrangement 
‘The case related by him is very interesting. Perhaps the Scuppers to the engine room helped to drain 
the space. It is agreed that tarpaulins are invariably fitted on the tonnage hatch opening but it is against 
regulations. Provision is made in the tonnage well that in the event of water finding its way through 
the spaces between the wood covers it can free itself by means of a scupper and a freeing port in the well, 


The ideal watertight steel hatch cover is probably not yet evolved. Lightness, mobility and stowage 
would seem to be the lines on which ingenuity should be concentrated. Their strength and the means 
employed for keeping them in position when closed seems to be a matter about which there is little 
dispute. Consequently it seems a much less hazardous proposition for underwriters, and a reduction in 
insurance premiums would therefore seem feasible. 


Mr. Johnson says the wood cover system is easily handled. Unfortunately it is also easily mishandled. 


His suggestion that dunnage should be placed on the tarpaulins before a deck cargo is carried is good. 
There must be a considerable amount of damage done to tarpaulins by cargo carried on the deck. 


Mr. Jackson suggests that legislation should be brought in making it compulsory for steel hatch 
covers to be fitted to all exposed hatchways. Much as one would desire it, I am afraid it will be some 
time yet before the steel cover will be a compulsory fitting. Nevertheless, the majority of ship's officers 
with whom I have discussed the subject are of the opinion that it should be compulsory for the No. 1 or 
forward hatchway to have watertight steel covers. The sketch referred to by Mr. Jackson is, J think, in 
order. It is the arrangement as contemplated by the Convention Regulations and these do not require 
doublings at the end of web beams. 


Mr. Jackson gives the correct answer as to why small bunker hatchways on the bridge deck should 
sometimes fail. The wood and tarpaulins are rarely ever new but made generally from discarded 
materials but from some of the other hatchways. 


Mr. Hjernquist suggests that end coamings should be stiffened similar to the side coamings. This 
is a good suggestion as it would ensure a more rigid frame work to the deck openings. He asks how much 
clearance there should be on the bearing surfaces. When examining hatchways it is a point. which very 
often causes one to think whether the particular fore-and-after or wood cover is too short. There is no 
hard and fast rule, but personally, I get the cover pushed hard against the opposite stop, and if more than 
half the bearing surface can be seen, | recommend renewal. 


>| 


Mr. Hjernquist says that the tanker would be just as safe if the hatchways were fitted with wood 
covers and tarpaulins. This is probably correct yet the rules demand that if a tanker desires the deeper 
loading she must have watertight stecl covers fitted throughout, including the hatchway to the forward 
or dry hold. 

Mr. Shepheard is surprised that the bunker hatchways on the bridge deck can be stove in. Mr. 
Jackson in the last paragraph of his contribution very correctly gives the reason for this eventuality, 
His description of the fatality when two men lost their lives is interesting but one could scarcely say that 
it was entirely due to the fault of the covers having steel bands. 


Mr. Houston thinks that if a vote were taken amongst nautical men on steel versus wood covers, the 
latter would win. About eight years ago when the Load Line Committee were examining witnesses, the 
most of them were nautical men, and the majority voted thus. Principally because they said they had no 
experience with steel covers. Since that date many ships have been equipped with steel covers and [ think 
if the question was now raised and witnesses examined who have had experience in the handling of steel 
covers, a different conclusion would be reached. 

Regarding the ripping of tarpaulins, I find that they either rip along the seams or between the 
coaming edge and the battening iron. The constant doubling under the battening iron. and the 
punishment they receive from mis-directed hammer blows deteriorates them so that ripping along the 
coaming side takes place, 


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SEAMLESS STEEL TUBES. 


By G. T. CHAMPNESS. 


Reap 47H Frsruary, 1937. 


In the first part of this paper the author has endeavoured to give an idea of the evolution of the 
seamless tube. There are developments of purely historical interest which have been omitted, since it 
has been intended to mention only the fundamentals of the processes. It is hoped that an understanding 
of the difficulties with which the manufacturers have been faced will be of assistance to those colleagues 
who have not the opportunity of being associated closely with the various processes. 


Some of the general remarks will be considered elementary, but since they are necessary to the 
continuity of description, it is hoped that they may be treated with indulgence. It is not intended to 
attempt any remarks on design or materials, as these subjects have been fully discussed in technical 
journals by persons more properly qualified to do so. 


The following subject matter refers to tube manufacture and inspection within the author’s experience, 
principally in plain carbon material. It may be stated that the carbon contents most frequently in question 
are those of “10 per cent to “15 per cent and +15 per cent to *20 per cent for boiler tubes and steam pipes 
respectively. 


In these steels the sulphur and phosphorus are specified not to exceed ‘04 per cent and manganese 
varies between 0°3 per cent and 0°7 per cent. Tubes for steam temperatures exceeding 750° F. of 
Molybdenum alloy steel are dealt with occasionally. The methods of manufacture of both plain carbon 
and alloy steel tubes as described are fundamentally similar, it being necessary with the latter materials to 
exercise the strictest control of temperatures. This detail is mentioned in the section dealing with heat 
treatment. 


HISTORICAL. 


The manufacture of seamless tubes is a comparatively recent achievement, and as in many similar 
instances this is mainly due to the early difficulties of producing a uniform, homogeneous steel of the 
right physical and chemical properties. This lack of homogeneity resulted in the material developing 
defects in the process of being drawn into tubes. The piercing of the billet in an economical manner 
was also an obstacle to the tube manufacturers; the early method of drilling the billet proving both 
costly and slow. 


The manufacture of most non-ferrous tubes commences with a cast shell or short cylinder, which 
passes direct to the rolls or draw bench. Steel has not the same facility for being cast readily into 


2 
hollow blooms, and the first stage in the production of seamless steel tubes is the formation of an initial 
bore in the solid billet. 


The early method of drilling the billet is clearly too lengthy a process for modern outputs, but it 
may have had the virtue of tending to eliminate central segregations. With piercing by mandrel or 
bar, any defects or impurities which may have existed in the rolled billet tend to accumulate at the rear 
end or bottom, according to the type of piercing process. Subsequent rolling and cold drawing intensify 
defects which may have existed in the first place as minute fissures. 


The development of improved piercing processes and the production of a uniform quality of mild 
steel occurred almost at the same time, and the necessary impetus to the industry was provided by the 
adoption of the seamless tube in locomotive and marine boilers. 


It is on record that as early as 1837 Hanson produced steel tubes by forcing steel through a small 
orifice around a punch, 


The method adopted by J. D. M. Stirling in 1854, which seems rather comprehensive, was that of 
“casting steel into cylindrical forms, and extending them by hammering, drawing or rolling, or by a 
combined process.” He mentions that it was preferable to cool first, and anneal subsequently. His 
method, and in fact the early trend of experimenters, showed the influence of the old methods followed 
in making tubes from the more ductile non-ferrous metals. 


An interesting development some thirty years later was due to W. H. Brown of New York, who 
manufactured drawn steel cylinders and tubes from discs of steel. The preliminary cupping was 
performed hot, and the latter operations of pressing, condensing, solidating [se] and tempering 
in the cold state. With modifications this is one process at the present day in the production of 
gas bottles. 


A so-called improvement of this patent was the performance of all the operations in the cold state, 
the long “cup” so produced being decreased in diameter as it passed through a series of reducing dies. 
In the same year the Mannesmann process of piercing was patented, and the seamless tube as a 
commercial proposition really dates from this time. 


PIERCING PROCESSES. 


The Mannesmann process is based upon the fact that the cross-rolling of a heated bar of steel produces 
a rupturing of the material along its centre line, and a tendency to form a hole along its centre axis. 
This may be made more clear by reference to Figs. 1 and 2. The shape of the rolls combined with 
the pressure on the billet stretches its surface, and makes it roughly oval in section as it passes the point 
where the diameters of the rolls are greatest. 


This deformation induces a central weakness, or even a cavity, and it was indeed possible to produce 
a Mannesmann shell with closed ends. This fact was discovered quite accidently during experiments with 
various forms of rolls. 


The early Mannesmann rolls were simple conical sections, the distance between their axes 
increasing from the smaller to the larger diameter. In order to control the diameter of the hole, and 
the thickness of the billet walls it became necessary to introduce an opposing mandrel. Further 
experiments led to the re-designing of the rolls so as to have a converging inlet and diverging outlet 
pass, in which the conical shaped mandrel was located. The rolls rotate in the same sense, and at 
the same time the relative inclination of their axes imparts to the billet a slow advancing movement over 
the mandrel. 


Fig. 1 shows a design of Mannesmann rolls, whose axes have a total angle of relative inclination in 
a vertical plane of 10 degrees. Fig. 2, an end view shows the location of the billet about one inch 


above the axes of intersection of the inclined rolls, restrained in an upward direction by a steady roll, and 
supported beneath by a guide. In some designs, each roll has a parallel section at mid length, which 
may extend for a third of the total length of the roll. 


Kote Ay1$ 
=- —- - —- — -Bruer Axis 
Ro, Axle 


Sketch A shows the location of the billet axis relative to the axes of the rolls. In the words of the 
original patent ‘The process consists firstly in imparting to the piece to be rolled a rope-like twist as 
regards the outer fibre.” This was due, of course, to the different peripheral velocities of the coned 
portions of the roll surfaces. The merits of this “rope-like twist’? seem to have been open to question, 
as the next development of note was the Stiefel process, of which the object was “to pierce metallic 
blanks or billets in a heated state without subjecting them to torsional strain or materially disturbing 
the longitudinal arrangement of the fibres.” 


Stiefel’s contention is hard to appreciate, as the examination of rejected billets from both Mannesmann 
and Stiefel piercers indicates definite twisting of the fibre. In any case, the ratios of velocities at outer 
and inner edges of the Stiefel discs suggest a very appreciable distortion. A pair of Stiefel discs are shown 
diagrammatically in Pig. 3 which should be selfexplanatory. An opposing mandrel is employed as in the 
Mannesmann process, and top and bottom guides steady the billet. 


The rejects among billets from the Mannesmann piercer show not only an approximately helical split, 
but one with slightly lapped edges in way of this split. It should be mentioned here that a more frequent 
cause for rejection of billets after piercing is irregularity of sectional thickness. 


Since the Stiefel rolls are capable of adjustment, not indicated on the sketch, the occurrence of both 
helical and approximately straight flaws in any one batch of rejects, indicates an optimum setting which 
produces no distortion of fibre. Unfortunately for Mr. Stiefel, in practice, this setting does not appear to 
coincide with the most economical speed of production. 


The author has etched specimens on sections at } in. below the surface of rejected billets direct from 
both Mannesmann and Stiefel piercers, marking in each case the axis of the billet on the sections. No 
directional grain flow was apparent, and after polishing and micro-etching, examination under the 
microscope showed in each case a typical normalised structure. On the other hand an etched specimen 
taken from the surface of the finished hot-rolled tube, showed regular and parallel banding, if one may 
use the term, of the pearlite constituent in the direction of rolling. ‘This banding persists from the ingot 
as a characteristic of the rolled bar, and the rolling of the tube provides the “twist.” It is concluded, 
therefore, that since the billets are pierced ata temperature of about 1250° C., and that the process occupies 
a matter of seconds, all the work is done above the upper critical, and grain flow is not in question. 
The tube, however, may leave the mill at 750-800° C., judging only by the colour, a temperature 
which would permit some directional effect, 


Applying these remarks to the finished tube, it is suggested that the ratio of longitudinal working 
to any original distortion should preclude anything but an axial fibre in the final article. For example, 
a typical 2} in. x }in. boiler smoke tube might be rolled from a 3 in. billet weighing about 120 lbs., and 
3 ft. 6 ins. in length. This billet would roll to 16 ft., giving a longitudinal rolling ratio of about 4:5, 
The ratio would be even more in the case of smaller sizes, where reducing operations were effected as 
demonstrated in Sketch B. 


Bitrer Furnace. 


Sketcn B. 


HoT BILLET 
34° op x 20 


PIERCING 
MILL 


JNTERPRETATION OF Pierceo Bucet 


Hot Finisning & 34" 0.p.xh x 40. 


Coro Drawine, “iF 


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DRAW BENCH. 


: FURNACE. 
RE - HEATING 
FURNACE. 
HoT PICKUNG 
DRAW BENC Bos. 


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Finally, considering that the strength of a tube subjected to internal fluid pressure is a function of 
the hoop siresses induced, it seems paradoxical to emphasise the importance of longitudinal fibre; and 
where two-dimensional stresses are involved, as in the case of a Scotch boiler smoke tube, which, with low 
rates of heat transmission is subjected to simultaneous hoop compression and axial tension, the 
disadvantages of a helical fibre appear even more evident. 


A third method of piercing introduced a few years earlier than that of Stiefel was the Ehrhardt 
process, extant at the present time in the Push Bench Process. 


In the original process the billets were of rectangular or “Gothic” section, and from the heating 
furnaces were dropped into a hollow cylinder, a pointed core bar then being hammered or pressed into the 
hot metal and guided by the lid of the cylinder. A Gothic section approximates to a square with 
rounded corners and slightly convex sides. 


Although the design of these sections varies, a common type has a side radius equal to the length 
across corners. (othic sections are not popular, as these “fishbacks,” as they are termed in the works, are 
difficult to handle in the furnace. Obviously the cylinder hore and the diameter of the core har are 
correlated to the dimensions of the billet. 


In the modern application the core bar is not pointed, and is secured to the crosshead of an hydraulic 
press. The billet is not completely pierced, and the solid portion at its base or ‘‘nose” subsequently 
engages to the head of the mandrel which pushes it through the dies. Fig. 5 shows the pierced billet 
before being withdrawn from the cylinder. The metal is displaced outwards to the bore of the cylinder, 
and, in addition some vertical displacement takes place. The introduction of this process of piercing 
was a commercial asset, as the square cogged billets were a cheaper proposition than the rolled bars 
used for rotary piercing. 


It should be mentioned that the piercing of rounds in all three processes now described is preceded 
by centering, which consists of placing the heated billet between a hollow cone at one end and a punch 
at the other, The punch is hydraulically operated, and forms the necessary depression to ensure a 
concentric start for the piercing plug. 


Billets are inspected at the stockyard, and any surface defects are removed by chipping, gouging or 
burning. The latter practice is not to be recommended, as a defect may be welded over and only 
discovered by subsequent chipping or gouging. The sawn lengths are then fed into the upper or cooler 
end of the heating furnaces, and roll, or are moved by hydraulic ram to the lower end, which is located 
near the centering and piercing plants. 


Before dealing with the production of the finished tube from the pierced billet, it may be well to 
adopt a precise nomenclature, in order to avoid confusion between hot-finished tubes and those that are 
cold drawn. 


From Sketch B it will be seen that when the pierced billet leaves the Pilger mill as a hot-rolled 
tube, it may take any one of four paths :— 


C. It passes straight to the operations of straightening, cutting to length, etc., when it requires no 
further reduction in diameter or thickness. ‘To be precise, this is a “ hot-rolled tube,” but the 
manufacturers prefer to use the term “hot-finished,” as this allows them the opportunity of 
correcting for size, if necessary, by subsequent hot or cold drawing, or reducing. 


B. “Stock” sizes of less than 12 ins. outside diameter are produced by reducing the rolled tube as 
described later in the section under that heading. 


A. Uncommon sizes, of which 14); ins. outside diameter may be taken as an example, are obtained by 
giving the rolled tubes several passes on the hot draw bench. 


1). In cases where a good finish is required in addition to a reduction in thickness as well as in 
diameter, the rolled tubes are reduced by several passes on the cold draw bench, with annealing 
and pickling between each pass. ‘The final tube is then referred to as “cold drawn.” The 
expression “cold finished” is inapt, as the last process ‘subsequent to cold drawing is always heat 
treating. 


6 


Sketch B is equally applicable, with modifications in machinery details, to the rolled tubes, or more 
generally to the “hollows” produced by the Automatic Process and the Push Bench Process. The 
subsequent operations of reeling, straightening, galvanising, etc., are dealt with in detail later in the paper. 
The sizes given on this sketch are purely illustrative, as it will be understood that a billet of given 
dimensions may form the basis of many different sizes and sections of tubes. 


PRODUCTION OF THE FINISHED TUBE. 


This is accomplished by one of three main processes :—The Pilger Mill, the Push Bench and, more 
rarely in this country, by the Automatic Process, 


Tue Pinger Min1..—This system is most generally employed in this country, and is undoubtedly 
the most interesting. The mill consists of two rolls, from each of which a part of the periphery is 
removed. This portion is termed the “Gap.” The remaining working surface has a circular groove, 
which has a varying section diminishing in the direction of revolution, 


A long steel bar carried by a feeding machine is located horizontally at the back end of the rolls. 
The hot pierced billet is placed upon this mandrel bar, and pushed by the feeding apparatus into the 
rolls. When the working section of the rolls comes in contact with the billet, the latter is rolled down 
and along the bar. At the same time the rolls push back the billet and mandrel until the “gap” 
rhe comes round, when the feeder drives the billet forward through this gap ready for a further nosing 

own. 


The system is seen to be a “step by step” process, the inside of the tube being in contact with the 
bar for only a short distance. The typical ridge formation in pilgered tubes indicates the advance 
corresponding to each revolution of the rolls. At each feeding stroke the billet is rotated through 90° 
by the charging mechanism, which incorporates a cushioning device and is quite a complicated unit. 


Fig. 6 indicates the contours of a Pilger roll, in which the entry of trumpet-mouth shape, the 
parallel semi-circular rolling groove and the gap may be seen. In this figure, the position of the billet is 
that of having been driven forward by the feeding mechanism, exposing a fresh surface of billet to the 
rolling grooves which are about to engage with it. The correct design and maintenance of the roll 
contours is important, and it is customary to employ men engaged solely upon turning them to a 
template, grinding and filing to a finished surface. 


The maximum size of tube produced by this process is limited to the power available for driving the 
billet and bar back into the roll gap. A minimum diameter may be taken as 1}-14 ins., smaller sizes 
requiring the additional operations of bench drawing or reducing by mill. 


Probably the largest tube produced, straight from the mill, in this country, and which may be 
considered as a commercial proposition is about 16 ins. diameter; aluhough diameters of 24 ins. are 
known to have been produced on the Continent. The maximum length of finished tube is governed by 
the allowable dimensions of the billet. Mr. G. Evans* mentions the manufacture of tubes 20 ins. in 
diameter, 5; ins. in thickness, and 30 ft. to 40 ft. in length. 


The revolutions of the Pilger rolls depend upon the tube section, and vary from about 50 to 
170 R.P.M. 


The following typical examples of Pilger practice show that the rolling speed, considered as an 
extension of the original billet, is approximately 12 ft. per minute in each case :— 
1. Billet 34 ins. outside x 2 ins. inside diameter x 30 ins. in length. 
Rolled tube 14 ins. x 6 gauge x 15 ft. 6 ins. in length. 
Revolutions of mill 165 per minute. Rolling time 60 seconds. 
2. Billet 5 ins. outside x 3 ins. inside diameter x 30 ins. in length. 
Rolled tube 3}ins. x fin. x 14 ft. in length. 
Revolutions of mill 105 per minute. Rolling time 58 seconds. 


*The Manufacture of Seamless Tubes. pp. 51-52. Gilbert Evans. 


‘ 


THe Push BencH.—This process employs billets pierced by the Ehrhardt system. This type of 
piercing was described previously as the formation of a “bottle” by the vertical hydraulic piercing of a 
hillet of rectangular or gothic section. 

The tube is produced by the insertion of a mandrel into the pierced billet, which pushes the latter 
through die rings, arranged in a horizontal bedplate, and decreasing in size successively down to the final 
required tube dimensions. This process is illustrated in Fig. 7 where the pierced billet is seen passing 
through the first ring die and entering the first guide ring. There may be as many as twenty dies of 
decreasing area, spaced about 3 ft. apart, with guide rings in between as shown. The mandrel has a tapered 
shank to fit the bar, and a withdrawing mechanism engages with the collar on the mandrel. The mandrel 
and pusher bar are loosely connected by means of a withdrawable locking plate. Owing to the heating up 
of the mandrels in the process, it is customary to employ a score or so of these in rotation ; no accelerated 
form of cooling is generally employed. 


The tube with the mandrel inside it passes from the bench to a reeling machine consisting of a pair 
of power-driven rolls, having their axes intersecting in the horizontal plane, which grip the tube at three 
or more points and impart to it a spiral forward movement. The rolls, of course, revolve in the same 
sense. This process serves the double purpose of imparting a good finish to the outside of the tube and 
of loosening the mandrel within it. 


As there is a mimmum limit to the diameter of a mandrel which can be used without fear of distortion, 
the smallest diameter of tube that leaves the bench is about 24 ins. and the maximum lengths are about 
18 ft. to 25 ft. Consequently some method of reducing is more or less integral with the Push Bench 
system, and generally takes the form of a reducing mill adjacent to the reeling machine. 


One modification of the Push Bench system includes a pointed nipple on the mandrel. By this 
means the “bottle” head is pierced as it enters the ring dies, and the tube can then be swaged or tagged 
for drawing when necessary, without a preliminary cropping to remove the solid end. On the score of 
economy of material this modification is commendable, but since by the nature of the piercing, any 
central segregations will be accumulated at the bottom or head of the ‘“ bottle,” the more general 
practice of hot cropping before swaging is more likely to ensure sound ends. 


For the largest sections further moditications of the basic process are necessary. In the Sheffield 
district tubes up to 24 ins. in diameter, 12 ins. in thickness, and up to 16 ft. in length have been 
examined. 


Billets of 12 ins. in diameter can be dealt with, and a 600 ton piercing press is employed. The 
number of ring dies for this size of tube seldom exceeds three, and two is probably general practice. 
For mechanical reasons, tubes of these dimensions cannot be cold drawn in the usual way, so that 
in these instances the tube is held stationary whilst the die is secured in the crosshead of horizontally 
operated hydraulic rams. 


The inventor of the Push Bench system claimed that the process enabled an inferior quality of 
steel to be used, at the same time resulting in a tube with mechanical properties equal to, or better than, 
the product of the Pilger Mill. The author has not received any support for this theory from the 
tube manufacturers, but it is worth a little consideration. 


From a practical aspect the straightforward compression effect seems to be as thorough as, and 
considerably less brutal than the distortion occasioned by rotary piercing, followed by Pilger rolling. 
Paradoxically enough, the Pilger type manufacturers maintain that the very strenuous nature of their 
process necessitates the use of billets of homogeneous quality. 


THE AvTomatic PRocEss.—This process employs a Stiefel type piercing operation followed by 
automatic plug rolling. The principle of plug rolling, a system of which the author has had no 
experience, involves the use of rolls having a number of semi-circular grooves of successively decreasing size. 

The pierced shell is fed into a groove of suitable size and is drawn by the rolls over a plug, which is 
held in position horizontally by a bar attached to a fixed head. The operation is repeated in successive 
grooves until the tube is of the required section. At the completion of each pass through the rolls, the 
tube, instead of being passed back by hand, is seized by a pair of smaller rolls operating in the reverse 
direction and passed back at high speed to the control side of the main rolls in readiness for the next 
working pass. 


8 


The return rolls, not shown in Fig. 8, which merely illustrates the elementary principle of plug 
rolling, are automatically opened off the tube whilst the actual rolling is being effected, and closed 
together on the tube for the return pass. This process has obvious limitations in respect of maximum 
tube lengths, internal finish and heat losses, but it is understood to have the advantage of a high speed 
of production. 


As a comparison with other methods of manufacture, it may be of interest to append a quotation 
from a paper read before the American Society of Mechanical Engineers (Iron and Steel division) which 
states:—“. . . the belief obtains to a varying degree in the steel industry that a better grade steel, i.e., 
a sounder steel is necessary with the Plug Rolling method than with the Pilger system.” 


It is understood that the automatic process is largely used in America and in Glasgow, and it would 
be interesting to hear from a colleague associated with this type of tube manufacture the reasons for 
its popularity in these areas. 


METHODS OF REDUCING. 


Coup Drawina.—Tubes which are intended to be finished by cold drawing are subjected to the 
same initial operations as those which are hot finished. Apart from the main advantages of providing 
accurate control of thickness, and producing a bright internal and external surface, the process reveals 
defects which might be difficult to detect in a hot-finished tube. As it is essential to pickle before cold 
drawing in order to remove mill scale, reference to this operation will he made later, and also to the heat 
treatment which is customary after each pass. The typical drawbench is well known, and merits only a 
brief description. 


Fig. 9 illustrates the usual chain bench, which consists of a square-linked endless chain running over 
a wheel located beneath the die, traversing the top of the bench, passing over the driving sprocket at the 
end of the bench, and returning below the bench. 


The steel die, the entry of which is generally trumpet shaped is contained in a fixed head of heavy section. 
A draw-carriage on wheels is freely mounted on the surface of the bench, and grips by means of 
tapered wedges the end of the tube, which is swaged down or “tagged” for that purpose. The carriage 
is fitted with a strong hook, which is engaged with the chain by hand operation. The tube is pulled 
over the draw bar, of which the head or plug is located within the die to form, with the latter, the 
annular space through which the tube is drawn and reduced in section. 


The plugs are frequently chromium plated to minimise wear, and are inspected in some degree by the 
operatives between each pass. Lubrication is effected by soft soap, oil or graphite, whose residual traces 
on the tube, when it goes into the annealing furnace, contribute to the scale and blisters on the inner 
surface of the tube as it comes from the furnace. ‘be lubricant exists in such profusion around the dies, 
that the inspection mentioned above consists largely in feeling the surface of the plug. 


The merits of fixed or floating dies, as an influence upon irregularity of wall thickness are apparently 
controversial. The question loses some of its significance for one who spends some time at the 
drawhenches, and watches operatives juggling with small pieces of tin between the die and the holder. 


Since the free length of tube frequently approaches the die out of line, some flexibility of die and draw 
bar would seem to provide a factor of safety. For the cheaper classes of work, the tubes, after swaging 
down for the drawbench are immersed in a hot solution of copper sulphate and brewers’ barm. This 
serves as a form of lubricant, and blacklead is used at the dies. This process obviates a certain amount 
of heat treatment between light passes, but is becoming obsolete. Larger tubes of comparatively heavy 
section, say 6 ins. diameter by ,; in. in thickness are frequently cold drawn on a heavier type of bench. 


The tube end is partially swaged down, and a bolt inserted so that the screwed shank protudes, and 
the bolt head fits the swage of the tube. The bolt screws into a crosshead loosely fixed to a toothed rack, 
which is moved parallel to the bench by a pinion, driven, in local practice, by a steam engine. 

Small tubes of heavy gauge are drawn over a plug in the usual way until such time as the inside 
diameter is too small to allow of the smallest plug. Further reduction then takes place with no central 
plug, when some experience is necessary to prevent cracking of the inner surface layers in their 
unsupported state. Tubes are produced locally 9 millimetres outside by 4 millimetres inside diameter, 
from Pilgered hollows 8} ins. x 24 ins. inside diameter. 


The work hardening due to cold drawing, and the necessity for subsequent heat treatment is 
indicated by the following test figures selected at random :— 


Billet analysis :—C. +126, Si 026, 8-028, P °028, Mn “45. 


and cold drawn in six passes to 1} ins. 0.d. x 11 gauge. 
Annealed at 700-730° C. and pickled between each pass. 


Finally close annealed at 920-950° ©. for 24 hours, and cooled in air. 


Pilger rolled to 17 ins. o.d. x 6 gauge, 


MAXIMUM) ELONGATION 
YIELD. STREss, PER CENT, 
| Tons. Tons per | Tons per | On2 | On 8 
sq. in. sq. in, ins. ins, 
As rolled “6c aa een teas OSL 19°2 20°25 59 Zo 
After last pass ee 29°1 3115 PPA) ac 
After final annealing... 5:9 1545 23°6 oF 35 
| 


The requisite number of cold passes depends upon the total amount of reduction in diameter and 
thickness required. It may be stated as a general rule that a 20 to 30 per cent reduction of sectional 
area per pass is aimed at. Some typical examples of drawbench schedules are appended :— 


REDUCTION OF AREA PER PASS 


PILGERED TUBE FinNAL TUBE 


| 
1" x 6G IF x 1G. | ast 30% | mnd24% | ard 205% | | 
14” x 7-8G. | 13" x 184. eePe MIT) Geese y air a0es 
138" x 7G 1” x 12G » 80% 4 MOIS yy Sle arse 


In these examples the tubes were annealed and pickled between each pass, and close annealed after 
the final pass. 


Hor Drawie.—Reference has already heen made to the hot draw bench for the reduction in diameter 
of the tubes as they-come from the mill. This process is employed when no reduction in wall thickness 
is required. It is analagous to cold drawing inasmuch as the tubes are pulled through a die by a 
carriage linked to a chain, but there are fundamental differences. 


Since all the work is performed with the tube at red heat, the speed of drawing is necessarily much 
higher, and the tubes are returned to the furnace, which is adjacent to, and in line with, the draw bench, 
after each pass. These partial re-heats are only of sufficient duration to permit the next size of die to 
be fitted; about six or so tubes being dealt with at each size of die. After three or four passes the 
batches of tubes undergo a complete re-heat, unless the total reduction can be effected in six or seven 
passes. During this operation of a complete re-heat, some care is necessary to avoid local concentration 
of heat and consequent local stretching. 


A jet of water is sprayed on the die during the drawing to cool it and to remove outside scale. The 
reduction of a 24 in. hollow down to a tube of 4} in. diameter requires eight passes, possibly with a 
complete re-heat after the fourth and seventh passes. The re-heat in this case will be necessary in 


view of the sawing and tagging occasioned by an approximately five-fold increase in tube length. 


An example from experience is the reduction of a 2 in. x ,% in. hollow to 1} in. tubing in seven 
passes. During the process the tube thickness was increased by about half of one gauge. This example 


suggests a general figure of an } in. reduction in diameter per pass. 


10 


In practice, however, the first pass is generally a heavy one, so that on the basis of percentage 
reduction of sectional area per pass, the figures for this example would be about 30 per cent for the first 
pass, 20 per cent for the second, decreasing pro rata to about 12 per cent for the last pass. 


Repucine Mi1..—The reducing mill, mentioned in the section of this paper dealing with the Push 
Bench process, consists of a number of pairs of rolls with semi-circular grooves, set alternately horizontally 
and perpendicularly. Each successive pair of rolls revolves at a slightly greater rate than the pair 
preceding it, and thereby effects a drawing out of the tube in conjunction with the sizing effect of the 
semi-circular rolls. In this form of reducing, as with hot drawing, a slight thickening of the tube wall 
occurs, and is allowed for accordingly. 

A development of the reducing mill, which is now Continental practice, involves four grooved rolls, 
set diametrically opposite with respect to the tube section, so that their grooves embrace the whole 
circumference of the tube. This is the Stiitting method of reducing, and may be considered in principle 
as the combination, in one plane, of one pair of horizontal and one pair of vertical rolls of the ordinary 
reducing mill described above. 

The effect of successive pairs of rolls is for the tube to assume a slightly oval section, with the 
minor axis alternately horizontal and perpendicular, according to the axis of each pair of rolls. The 
Stiitting mill ensures a circular section throughout the operation. 


A mill of similar type, known as the Quarto-Mill, is in use in this country, and consists of a series 
of grooved rolls arranged in fours, each group of four rolls haying smaller grooves than the preceding 
group. Experiments carried out locally with this mill resulted in the reduction of a 22 in. Pilgered 
hollow to tubing of 33 in. diameter in one operation without re-heating.. This makes an interesting 
comparison with the example given in the section headed Hot Drawing, of a 2% in. hollow reduced to 
4} in. diameter in eight passes, with two complete re-heats, sawing and tagging. 


HEAT TREATMENT. 


There is little parallel between the practice of heat treating forgings and the heat treatment of tubes. 
In the latter case the individual masses are small, and the furnaces are precision instruments. By this, 
it is not meant to imply that forging furnaces are deficient in this respect, but at the tube works one 
cannot conceive the elastic, coal fired, brick built annealing furnace built into the forge foundations, and 
fitted with pyrometers which provide accurate record of the supply of heat, but leave something to the 
imagination in respect of uniformity of heating of the forgings. ‘This type of furnace, designed for forge 
annealing only, is by no means rare; but is in a different category from the muffle furnaces which allow 
of accurate control of air supply as well as fuel. The design of furnaces for steel tube heat treatment 
varies in detail, but the general type will be familiar to most of us. 


Furnaces up to 40 ft. in length are employed, but the side-fired type of dimensions about 6 ft. wide 
by 20 ft. in length is probably typical. They may be fired by town gas, producer gas or oil; temperature 
is indicated by recording pyrometers. 

Some firms, notably one in Sheffield, employ the continuous type of furnace, in which the tubes are 
conveyed on belts, or on a protected roller hearth. In the latter process the rollers, which are encased in 
firebrick are arranged in sections, which are rotated at various speeds according to the position of that 
section in the furnace, and the corresponding temperature. This type of furnace has two or more 
optical pyrometers according to the heating stages of the system. The main essentials are uniform 
temperatures, accurate control, and in all cases—with one exception to be mentioned later—contact of 
the products of combustion with the tube surface is to be avoided. 


When freedom from all scale is necessary, the “close annealing” process is adopted. In this case 
the tubes are enclosed in large pipes, sealed at their ends with caps and fireclay, or arranged in shallow 
trays whose lids are sealed at the edges with sand. The resulting surface of each tube is free from 
scale, a desideratum when electro-zincing is subsequently performed. 

There is some looseness of expression with respect to the heat treatment of tubes, almost any form 


being termed “annealing.” It may be stated that true normalising, i.e., in order to obtain refinement 
of the grain structure by heating to about 880°C. for a “18 carbon steel and cooling in air, is only 


employed when hot working has been prolonged at too low a temperature, and a poor material structure 
has resulted, or as a final treatment after cold drawing when, as in each of these cases, a complete 
refinement of the structure in respect of the excess ferrite as well as the redistribution of the pearlite is 
required. This contingency may arise with Pilgered tubes if the finishing temperature should fall below 
that at which the compensating annealing effect is operative, or when any discontinuity in the process 
should occur. 

If the rolling is continued down to, but not below Arl, a fine grain and moderate tensile strength is 
to be expected, but any rolling continued below this critical will, of course, result in distortion of grain 
and decreased ductility. 

The heat treatment between passes in cold drawing, and in all cases where a lowering of tensile 
strength and improved ductility only is required, consists of heating to just below the lower critical, 
(650°-700° C.) and holding at this temperature for about half an hour, followed either by some form of 
retarded cooling or by free cooling on the floors, 

Care has to be exercised both in heating and cooling, for in these low carbon steels the change into 
the austenitic condition takes place rapidly, and it should be remembered that a cold drawn tube as it 
comes from the drawbench is in a highly stressed condition. Steel in this state, when heated, exhibits the 
phenomenon of intermolecular lag or inertia; the stresses tending to persist even when the structure of 
the material has been changed completely by the annealing temperature involved. 

The cooling of the furnace as a result of charging with cold tubes is illustrated in the following 
example from experience :— 

A number of 1} in. x 10 gauge cold-drawn boiler tubes of ‘15 carbon material were loaded at 950° C. 
and the furnace temperature dropped rapidly to 890° C., reaching the designed 950° C. once more in 
35 minutes. After a definite period these tubes were turned by hand through 180° to ensure homogeneous 
heating, and finally cooled in the furnace for six hours. This cooling would ensure a complete 
coalescence of the excess ferrite, and a maximum ductility. 

In comparing the two methods of cooling for steel of such low carbon content, in which the proportion 
of pearlite is probably less than 20 per cent, the air cooled tubes may show an increase in tensile strength 
of about 15 per cent over those cooled in the furnace, and a corresponding reduction in the figure for 
elongation. 

If the saturation at high temperature has been sufficient to obliterate entirely the initial structure 
and to overcome the tendency to return to the strained condition, then it is probably immaterial what 
method of cooling is employed. But if complete diffusion has not taken place, cooling on the floors will 
give as little opportunity as possible for the reappearance of the original structural tendency. 


The question depends largely upon the initial condition and structure of the steel prior to heat 
treating. The influencing factors may be large cold-drawing ratios, or in the case of hot-finished tubes, 
unduly high billet soaking temperature, or low finishing temperatures. In any event, the lowest 
temperature will be used which produces the desired result. 

A form of low temperature annealing for bright (ie., cold drawn) tubes termed “ bluing ” consists of 
heating to a temperature below Acl, generally about 850°-400° C., in an open furnace. By this means 
a film of oxide is imparted to the tube surface as a form of protection. 

In view of the amount of discussion which it has been found necessary to hold upon the merits and 
demerits of protective scaling, it is of some interest to note that a large number of tubes of ‘“ Corrostite”’ 
(copper alloy) material were ordered recently for locomotive boilers. ‘These were to be supplied in two 
lots, one scale free and the other heavily scaled. In due course a repeat order was received from the firm 
in question asking for all the tubes to be supplied in the scaled condition. 

The question of billet soaking temperature, if a digression may be allowed, is of special importance 
where alloy steels, particularly nickel steel billets, are involved. Steels containing this element have a 
tendency to'scale heavily at high furnace temperatures, and a billet that is allowed to become scaled in 
this manner emerges from the Mannesmann piercer covered with small “Japs,” having a pockmarked 
appearance. The obvious remedy is so to control the soaking temperature that the billet is not held in 
the scale-forming area for any length of time. At the other end of the process, the tendency of 
some alloy steels to air harden necessitates tempering before the subsequent operations of cutting and 
manipulating. 


12 


PICKLING. 


Steel oxidises rapidly at red heat, and the removal of scale by pickling is necessary before further 
cold drawing or electro-zincing. The pickling baths or “boshes,” as they are termed, are lead lined, 
or brick walled with timber linings, and the fluid, generally commercial hydrochloric or sulphuric 
solution, is kept in constant agitation by jets of steam. 


A common method of dipping the tubes is by holding them in a belt or chains, which may be 
arranged to rotate the bundles in order to effect a renewal of pickling solution inside, and to prevent 
deposit of pickling residue in the tubes themselves. Water boshes for rinsing purposes are generally 
adjacent to the pickling boshes, and this swilling is of importance, as the smallest particle of scale or 
hard deposit remaining in the tube end may occasion a draw line or score during the first subsequent 
pass on the drawbench. 


The pickling fluid in general use is commercial sulphuric, and only in the best class of work is 
hydrochloric employed. The latter process takes longer, and is necessarily more thorough. It is a low 
temperature process and has advantages of a chemical nature. Further remarks on pickling will be 
made in the section of the paper dealing with electro-zincing. 


SUPPLEMENTARY PROCESSES. 


STRAIGHTENING.—This is an essential operation after cold drawing and heat treating, after reducing 
in the hot state, and for rolled tubes which undergo no further reducing. When in the bright state, 
and consequently in a hard condition, the tubes are straightened by passage through a reeling 
machine, comprising three or more concaye rolls with inclined axes, and rotating comparatively 
slowly. By this means a finish also is imparted to the tube surface. Hollows from the Push Bench and 
Pilger mill are also straightened by reeling, but annealed tubes in the softened condition are straightened 
manually and by eye up to about 24 in. o. d. in the lighter gauges, and larger sizes and sections in a press. 


The somewhat primitive looking bending racks used in straightening by hand occasionally leave a 
slight ridge in the tube surface. This is readily detected when sighting internally, although sometimes 
difficult to detect on the outer surface of an annealed tube. 


Where specified limits of straightness are fine, or where short lengths are in question, these tubes 
are straightened on a press in conjunction with a clock micrometer; the tubes being freely mounted 
between centres. As a corollary, it may be mentioned that tubes have been presented for hydraulic test 
and final inspection after having been bent cold. 


Whilst a small degree of bending is a question for the Surveyor’s discretion, it should not be 
necessary to state that all tubes subjected to any considerable amount of cold bending ought to be 


annealed before hydraulic test and inspection. In many cases this is rendered necessary in order to deal 
with the ovality produced by such treatment. 


As an example, the author found that when a large number of straight lengths of 3}in. x 7 gauge 
boiler tubes had been bent cold through about 30° to fit a template, this procedure resulted in an average 
difference of a quarter of an inch between major and minor axes in way of the bend. In this instance, 


annealing after all cases of cold bending was required by the specification. 


ELEcTRO-ZINCING.—A|though electro-zincing is hardly within the scope of this paper, a few remarks 
may be of interest if only because the process facilitates inspection. The protective action of electro- 
zincing consists in the layer of comparatively pure zinc hermetically excluding the material of the tube 
beneath from contact with oxidising conditions. 


The tubes are necessarily pickled as a preliminary operation, and washing always follows to prevent 
the reaction of any residual pickling solution with the tube and atmosphere to form iron salts. For this 
pickling, hydrochloric solution, or as it is termed muriatic acid, is employed, and not the commercial 
sulphuric which constitutes the pickling fluid used prior to cold drawing. In addition, washing with soda 
solution is practised in order to remove any possible grease, which exhibits a high electric resistance, and 
is liable to produce black patches on the finished surface. 


——— 


In contrast with hot galvanizing, which involves the formation of an iron-zinc alloy overlaid with 
a film of crude primary zine, electro-zincing produces a film of pure electrolytic zinc about fifteen 
thousandths of an inch in thickness, +t depending upon time and electric variables. An even tube wall 
thickness is important in order to present an equipotential surface, and consequent even film thickness. 


The electrolyte is principally a zine salt solution, with possible additions of alum, mercury salts and 
some organic substances to improve the finish and add lustre. 


Direct low voltage current is employed, zinc plates constituting the anode, and the tube itself the 
cathode. Several tubes are treated at one operation, uniformity of deposit being assured by supporting 
the tubes at each end upon plugs located near the periphery of slowly-rotated discs. 


In local practice these discs are rotated by chain and sprocket from an overhead drive. The 
finished tubes are washed, dried with steam, and stacked in the drying rooms for about twenty-four hours. 
‘Electro-zincing is supposed to effect a lowering of the yield point and tensile strength, due probably to 
hydrogen absorption, but the author has been unable to record any consistent results to substantiate this. 
There is, however, a reduction in elongation values, which is more noticeable in a plugged tube than in a 
strip cut from the tube. It is for this reason that electro-zinced tubes are frequently “boiled” after the 
process, particularly if, in the foreman’s opinion the pickling has been unduly prolonged. This treatment 
is known in the vernacular as “boiling out the acid,” and in support of this practice cases have been 
known of tubes overpickled which have split spontaneously when removed from the bosh. Of course, 
cold drawn tubes are always heat treated before electro-zincing, and are therefore not in the strain- 
hardened condition most liable to hydrogen brittleness. But in explanation it should be remembered 
that after cold drawing, even the low carbon material with which we are concerned is in a highly 
stressed condition ; one which may not be corrected entirely by the heat treatment. 


Sutton } states that during pickliag, the solution of the surface layer, with consequeut readjustment 
of any residual stresses may cause cracks in the newly exposed surface. This hydrogen brittleness is a 
temporary condition, and may be overcome by heating; the temperature of boiling water being sufficient. 
It is rarely that surface defects are noticeable on an electro-zinced tube, and those that may occur 
generally owe their origin to the pickling or washing operations. 

Swaine and ExpANnDING.—The swaging or tagging of tube ends for the draw bench is a rough 
process, carried out in the hot state, between rolls or multiple swaging hammers, and merely involves the 
breaking down of the tube end to form a tag suitable for gripping in the draw carriage. 


Swaging to specification for finished reduction of diameter is effected by a rotary machine which is 
rather difficult to describe. A number of steel rollers radially disposed, and with their axes longitudinal 
are free to rotate in a fixed outer housing. Revolving concentrically within them is a hollow cylinder, 
slotted transversely to take two diametrically opposed sliding blocks, whose inner faces hold dies with 
contours corresponding to the required tube diameter. 


Fig. 10 isa purely diagrammatic illustration. The outer face of each sliding block contains a roller, 
whose projecting surface engages with the housing rollers successively, as the central member revolves. 
The action of the machine is therefore a succession of rapid and positive blows upon the tube surface 
as it is fed into the dies. As in the case of reducing rolls, allowance has to be made for some thickening 
up of the tube walls, Needless to say the tubes are fed into the machine direct from the heating furnaces, 
and the operation is carried out at a bright red heat. : 


In the conyerse process, that of expanding or swelling, the heated end of the tube is gripped between 
dies in the vice of the machine, and a parallel plug is forced into the tube end simultaneously with the 
closing of the sizing dies round the “swell” thus formed. The process is generally repeated for a final 
sizing, that is to say the operation is carried out in two stages, and in one heat. 


Concentricity of swell with the body of the tube is a function of the relative positions of plug and 


dies, and it is difficult to account for inaccuracy in this respect, since the machines are particularly 
robust. 


Tarerep Tubes.—The art of manual welding is preserved locally in the manufacture of tapered 
tubes for waste heat and similar types of boilers. A typical tube of this kind may be 3 in. x 7 in. 


gauge, x 18 ins. overall and 10 ins. in the parallel length. The stages in the process of manufacture may 
be seen by reference to Fig. 12. 


{ “ Galvanizing.”—Heinz Bablik 1936. t Sutton. Jowrnal of Iron and Steel Inst. 1929, 


14 


The length of tubing, generally -05 carbon boiler steel is heated and swaged down under the steam 
hammer between tapered dies, provided with a stop as shown. ‘The small end is then placed in a grooved 
anvil and forged down with a nipple by means of a concave swage tool. The nipple is cut to the required 
length with a cold set, the tube is placed over a tapered mandrel corresponding to the final internal 
dimensions and welded over to form a rounded point by means of the hollow tool illustrated. During 
the tapering and swaging operations a thickening of section occurs, and a tube of the dimensions given 
above may be 5 gauge at the end of the taper and 3-4 gauge at the point. The tubes are annealed after 
fabrication. 


Although the rotary swaging machine might be adapted to effect the tapering, and the ends forged 
in by a spinning process similar to that employed for air receivers of certain types, little time would be 
saved on the actual work necessary. In practice an experienced man can produce these tubes at the rate 
of one every seven or eight minutes, so that small work of this description is dealt with efficiently and , 
economically by skilled labour. 


CorruGatinG.—The formation of corrugations on steam pipes is interesting on account of its 
practical simplicity. Unlike furnaces, where the shape of the corrugations is determined by the contour 
of the rolls, the folds are produced by simple axial pressure; the only restraint upon their formation 
being that of the distance moved by the feed screw, and uniformity of heating. 


Fig. 11 is intended to represent the principle rather than to indicate the type of machine involved. 
In machines used locally the axial pressure is controlled by independently operated motors. A central 
mandrel is supported in two fixed heads on the bed of the machine. At one end a collar on the mandrel 
abuts on the head and forms a thrust. At the other end is a hand-operated clutch whose outer member 
is part of a hollow shaft, square threaded on the outer surface, and running in a corresponding thread in 
the fixed head. The mandrel passes through the hollow clutch shaft, and is rotated at slow speed by 
belt and pulley or other suitable means. The pipe is gripped between two discs on the mandrel, one at 
the thrust end and the other forming part of the clutch. A circular gas ring provides a localised flame 
over three or four inches of the pipe length, and when the required temperature is attained the clutch 
is engaged for a few seconds at a time, the feed screw provides axial compression, and the corrugation 
is formed slowly and regularly. 


The resulting corrugations are frequently characterised by small surface cracks on the outer surface, 
running, not as might be expected, circumferentially, but in a longitudinal direction. 


The greatest problem of the manufacturers in thé early days of this process was to find material 
capable of standing up to the operation, and these small cracks, which may be removed with a fine file, 
persist even in material intended for the best class of work. In cases where the finished pipe is bent 
and flanged before annealing and hydraulic testing, the corrugations become more acute at the inner 
radius of the bend, but in the author’s experience the cracks do not extend or enlarge as a result. This 
fact, coupled with the direction of these cracks, would seem to indicate that their cause is due not so much 
to bending as to the increase in diameter. Three typical sizes of corrugated steam pipe are appended :— 


Nomina of. | Thickness, | Mayigum Diameter) Pitch of 
ae & ‘ s a | 
4 ins. 5 gauge | 42 ins. 17 ins. 
| 
7} ins. | } in. 8% ins. 23 ins. 
12. ins $ in. 144 ins. 3%} ins. 


From these figures it will be seen that in each case the percentage increase in diameter is about 
21 per cent, which is not a severe punishment when effected at red heat. Assuming that these cracks 
are not associated in some way with the raw material, it is suggested that their presence, in these low 
carbon steels, may be due to the successive heating of adjacent areas, with consequent retarded cooling. 


1D 


TuBE DEFECTS. 


In a finished tube defects may be due to mechanical considerations, or may be inherent in the billet. 
Probably the most frequent in the former category are draw lines and ridges. Draw lines and ridges may 
both be caused by lack of attention to the dies and plugs. Insufficient lubrication, coupled with possible 
oxide spots not removed by pickling, frequently results in a ridge formation in a cold-drawn tube, and 
ample warning of this trouble is given by the loud rattling noise occasioned by the interrupted motion of 
the tube over the plug. 


Seams, laps, splits and rough surface due to scale, may be traceable to the original billet or bloom, 
or occur as a result of faulty piercing. 

Small amounts of scale or pitting are not of any great moment, provided that their removal does not 
reduce the wall thickness to that below the specified minimum limit. Surface pitting may be due either 
to scale rolled into the surface of the ingot, or to the presence of smal! blowholes near its surface. These 
blowholes, during the soaking of the ingot, become filled with molten oxides, which cannot be removed by 
subsequent pickling, and which necessitate chipping or gouging of the billets. 


Such blowholes, and to a certain extent segregation, are a determining factor for the ratio of inside 
and outside diameters of the pierced billet. Obviously, the smaller the final annular section of the 
pierced billet in relation to the full section, the less the likelihood of the presence of these defects. 


It is for this reason, coupled with the suggestion of a “forging” effect that the Ehrhardt system of 
piercing, with its relatively thin shell has much to recommend it. 


Similarly, whereas a central pipe in the ingot may be of little consequence, secondary. defects of this 
nature, located nearer the ingot surface are liable, if not closed up during the rolling into blooms, to 
persist in the shell of the pierced billet as laminations. 


Laps, which persist from the billet to the tube surface if not detected, are due to faulty alignment or 
draught of the rolls, as a result of which a horizontal fin is formed on the surface and rolled over into the 
metal at the next pass. In the finished tube the laps are generally referred to as “ spills.” 


Seams or surface cracks develop occasionally as a result of these laps, and also as a result of scale or 
slivers rolled into the material and subsequently detached. These seams are a frequent cause of the 
rejection of billets during piercing, as also is irregular wall thickness which would persist during the 
rolling of the tube. 

Such defects are readily shown up by cold drawing, and since they may be to a certain extent obscured 
by the scaled surface of a hot-finished tube, the wisdom of polished ends to facilitate inspection is obvious. 


Occasionally cracks are attributable to torn surfaces in the cogging down of the ingot, which are 
subsequently imperfectly welded and covered by fresh scales. 


Chemical analyses are generally supplied by the manufacturers, but these are not necessarily a 
guarantee against possible segregation. Nor for that matter are they a guarantee of the suitability of 
steel of that analysis for tube making. Much depends upon the amount and nature of the non-metallic 
matter, of which the non-ductile inclusions interfere considerably with the flow of the metal in the 
manipulating operations. 


Since it is not the usual practice for Surveyors to be given unsolicited copies of billet analyses when 
attending at steel works, it is considered that the inspection, if any, of tubes other than those for water 
tube boilers, made from tested billets might well include the verification of sulphur prints from the billets 
in question, as required by the Rules in the case of rivet bars. This would not put the manufacturers to 
any additional trouble, as customer’s specifications frequently require a sulphur print to be taken from 
each end of a precentage of billets from each cast. 

In cases of longitudinal cracks at one edge of a three-way flattence in a batch of otherwise sound tests, 
it is the author’s practice to remove surface scale by light filing adjacent to the flattened length, and have 
the flattening extended in the same plane to cover this area. 

In many cases this additional test indicates a sound tube, and the original cracks to be due to rupture 
of firmly adherent scale acting as a “‘stress-raiser.” The strain at the edges of a face-to-face flattened 
tube is comparatively severe. 


16 


The author, whilst on steel testing duties carried out some tests to determine the percentage 
elongation at the extrados of some ordinary bend specimens. 


Datum lines were marked from mid-length on some ship quality steel test pieces, which were 
subjected to the ordinary type of “free” bending over 180°, in hich peaking invariably occurs. By this 
it is meant that a proportion of the strain is localised in the legs of the specimen. The results indicated 
an average percentage elongation at the extrados of 35 per cent. 


The flattening of a 4 in. or 5in. length of tube until the walls are almost in contact, is considered to 
be a more severe test than the above, and whilst a mere expression of opinion as to the percentage 
elongation likely to be experienced would be of little value, the elementary tests described above would 
suggest an extension at the exposed surface somewhat greater than the figure for the tensile test. 


The detection of internal surface defects by sighting the tube requires some experience. A newcomer 
will find it useful to examine the tubes already marked for rejection by the works inspectors. Incidently 
it will generally be found that a complete ring of chalk on the tube end is taken to infer rejection, and a 
small part of the end chalked to indicate brushing for further examination. 


Tubes that have been close annealed and polished, pickled or electro-zinced, present a bright internal 
surface which offers every facility for inspection. 


In hot-finished tubes, or tubes which have not been brushed and polished, it is difficult to carry out 
a satisfactory examination of the internal surface owing to scale, and the difficulty of adequate 
illumination. 


INSPECTION AND TESTING. 


IDENTIFICATION OF MarertaL.—There is some difficulty in checking the progress of any one cast of 
material to its final condition as finished tubes ready for inspection on the trestles. There is no 
corresponding difficulty in the steel works, where the ingot numbers correspond to the serial numbers on 
the bars. 

At the tube works, the material is received in the form of rolled blooms which bear the steelmakers’ 
cast number. The system is generally employed of painting the blooms with rings of colours, each of 
which represents a definite analysis, and in rare cases this system is applied to batches of finished tubes. 

A rolling order is received at the stockyard for, say fifty -10-—*15 per cent carbon billets of 56 Ibs. 
each. Blooms from a cast of this analysis are transferred to the saw, and the necessary billets cut to 
lengths. These billets bear no identification mark, but are stacked by casts near the furnace charger, 
and are checked with the copy of the rolling order received by the furnacemen. The identification of the 
tubes leaving the mill is therefore a simple matter, but since, in the warehouse, the tubes which bear no 
mark, are racked by orders and not by casts, subsequent identification may not be so positive. 

The warehouse office receives a copy of the rolling order, from which it can be ascertained that 
approximately so many feet of a certain size tube were rolled from the cast intended for that order. But 
this total length of tube as rolled, when cut up into lengths, is seldom exhausted by the one order, which 
probably includes tubes of different sizes. The surplus material, therefore, goes into stock, and can only 
be identified when utilised subsequently, by reference to past rolling orders. Furthermore, when tube- 
makers carry large stocks of tubes ordered from outside firms, for making into steampipe bends and 
straights, difficulty is frequently experienced in obtaining the mill sheets relating to the stocks in question. 

To make this clear, firm A orders from firm B 10,000 feet of 44 ins. x } in. and 3} ins. x } in. 
tube, which may be exhausted in a month. When this stock is getting low, the order is repeated, and 
the new stock is racked with the original without any means of identifying the two batches. As a first 
step to simplify these problems, it is now the practice in the Birmingham district, where “stock” size 
tubes involving periodical repeat orders, are concerned, to take representative tensile tests from the 
material of one complete rolling, before cutting up into lengths. The other mechanical tests are taken 
as and when the individual orders come along. The feetage is ascertained as accurately as possible, 
allowing for defective lengths and cropping, and subsequent orders for the tubes in question noted in feet 
lengths against the original stock, until it is exhausted. Any accidental inclusion of tubes from a 
different rolling of the same size, will become evident by an excess balance of stock lengths over the 
original record of tested rolling. This system applies, of course, to hot-finished tubes. 


17 


Inspection (Routinr).—Fig. 13 shows the sequence of events in a hypothetical tube mill layout 
of the Pilger Mill type. Actual plants differ from this plan only in respect of numbers of individual 
units, and their relative location. Before attending the works it is assumed that the details of specification 
and test requirements other than those of this Society will have been noted. A mill sheet giving particulars 
of the order with cast numbers is provided at the test house, and is taken to the inspection department. 

When the tubes have been identified, time may be saved by selecting and marking. test pieces first, 
as these may then be cut off and, if necessary, machined whilst the tubes are being inspected. Few 
testing machines are capable of dealing with a plugged test length of over about 24 ins. diameter by 10 
gauge, and the officials of the inspection department will advise a newcomer as to whether a machined 
strip is necessary. 

By the time the examination of the tubes is completed, the selected tests should be prepared and 
gauged ready for the tests to be witnessed. The number of tests to be stamped is, in the case of tubes 
for water tube boilers, defined in the Rules. 


Individual tests to cover each cast, if more than one is involved, and also to cover different thicknesses, 
should be taken. In regard to the latter point, it should be remembered that different thicknesses of 
tubing may indicate different roll settings, and in consequence a distinct series of operations, including 
that of heat treatment. For example, large numbers of 2} ins. x *128 in. plain tubes and 2} ins. x +25 in, 
screwed stay tubes are dealt with locally, the former being an entirely different rolling order from the 
“128 in. gauge tubes. 

Water tube practice in respect of the number of tests to be selected is generally adhered to for the 
majority of other types of tubes, but steam and feed pipes which may be of heavy section and large 
diameter are in a different category. Tests from these pipes, presented in straight lengths, are taken in 
accordance with the Board of Trade requirements as follows :— 


Tubes up to and including 4 ins. in diameter ............... .+se+eL in 40 or part thereof. 
» above 4 ins. up to and including 5 ins. diameter .........1 in 10 ,, i 
re Fae anh ated - = foins ee Ree kinite ts a * 
x Se ITS A ITIACIANOLCRS savethccesteg path aeons cer sgopoomile iia be a =f 


This requirement takes no account of thicknesses in which connection the Surveyor should be guided 
by steelworks practice. This is fully dealt with by Mr. W. D. Heck and Mr. J. M. Robertson in their 
paper “Steel Testing,” read before this Association. 

A knowledge of the system of manufacture involved has a bearing on the selection of tests, since by 
the Automatic and Push Bench processes comparatively large shells may be reduced to various smaller 
diameters in the reducing mills, a continuous operation. 


With Pilgered tubes, however, since one of the main advantages of this system is the production of 
tubes to finished dimension, é.e. without further reducing, one may assume in most cases that different 
tube diameters suggest entirely different rolling batches. This point may be verified by inspection of the 
rolling order, of which a copy is retained in the inspection department. 

Tubes for examination are generally placed upon trestles at a convenient height for sighting, gauging 
for thickness and diameter, and rolling for straightness and examination of external surface. Each 
selected tube is marked off in lengths of about 14 ins., 6 ins. and 2 ins. to cover respectively tensile, 
flattening and expanding, and crushing tests. 

A little point worth remembering is that it is as well to have the selected tubes marked off in such 
a way that the end of the tube is reserved for the expanding test, and not as is frequently observed, sawn 
off in a 14 in. length for the tensile test. 


‘ 


en rei ae Bae ja. a an 


Go Be 0 ee ae ie 
\ KEEP FoR EXPANDING TEST. 


SKETCH C, 


18 


Incidentally the crushing test, which involves a 2 in. length compressed lengthwise to 1 in. without 
sign of flaw, is not included in the Society’s Rules, but seems to be presented generally, as a matter of 
course, with the other mechanical tests. 


The three-way flattener is considered to be a most useful test as it indicates the ductility and ability 
of the material to withstand compressive stresses at twelve distinct parts of the tube surfaces. At the 
flattened portion at mid-length where internal examination is not possible, the opening out of a score or 
similar defect on the inner surface is frequently shown up by the failure of this area to present a flat or 
plane outer surface. In the extreme case of such a failure the tube would assume a figure-eight section, 
and for this reason the sides should not be presented closer than required by the Rules. 


The expanding or drifting tests may be dictated by practical considerations, and the comparatively 
few failures under this test are not surprising when the mild character of the punishment of the material 
is considered. The drifting test is usually carried out well in excess of the Rule Requirements, and even 
given a precentage increase in diameter of 12°5 per cent, i.e., a 2 in. nominal diameter drifted to 2} in. 
diameter, the strain on the tube wall is only about half the figure required for precentage elongation 
under tensile test. 


It is realised however, that in the process of roller expanding, the rollers exert a “ knuckling” action as 
they work round the mandrel, so that the tube is subjected continuously to a more severe deformation 
than would be suggested by a mere measure of expansion. 


The minimum Rule Requirements for precentage increase in diameter by drifting are interesting, 
placed side by side with the figures obtained by the familiar boiler shop * rule-of-thumb” of 4!y in. + 4!y in. 
per inch of diameter. 


PRECENTAGE INCREASE BY 


b>) c. 
HOP PRACTICE RULES (DRIFTING). 


1 in. dia. to 1,% in. = 94% Up to 10 L.S.G. = 9°5 % 
Biter see = oweoly ey os Gh Ate = 70% | 
BoUe sel ogy, her Wa oe Above 6 ,, nD 


If this is one basis for the Rule Requirement the author must apologise for being elementary. 


In the case of large tubes where the flattened ring is impracticable, the bend test should be carried 
out on a strip cut circumferentially. The test. is-occasionally called for in the tempered condition, that 
is to say the flattened strip is heated to about’ 1,350° F. and cooled in water at 80° F. It would be 
interesting to know whether there is any supposed metallurgical basis for this temper test, or if it is merely 
intended to indicate the behaviour of the material of the tube in the event of the introduction, in 
practice, of cold feed into an overheated tube. 


It is sometimes experienced that a batch of tubes has to comply with a specification calling for a 
certain percentage elongation on a test length of tube, which has steel plugs inserted at each end for 
supporting the tube in the grips of the machine, when the diameter of the tube precludes its admission 
into the testing machine. It is then customary to carry out the test on a milled strip, and adjust the 
required elongation accordingly. 


19 


The following figures taken from the British Standard Specification for cold drawn weldless steel 
boiler and superheater tubes for designed temperatures not exceeding 850° F. may be of assistance in 
these instances :— 


ULTIMATE TENSILE. MINIMUM ELONGATION PER CENT. 
rt Se ee, Ce E. a es 
| Minimum. | Maximum. ; in. thick and over. Less than } in. thick. 
| a — is —— —— 
| Tons per | Tons per 
sq. in. sq. in. On 8 in. | On 2 in. | On § in. On 2 in. 

A | 20 26 20 32 18 30 

B 20 26 28 Bh) 28 3D 


The corresponding figures for hot-finished tubes of the same type are as follows :— 

A 28 22 20 — 18 = 
B 28 20 25 — 23 — 
A = Strips cut from tubes and tested in the curved condition. 

B = Test lengths taken from finished tubes, with ends plugged for grips. 


Cases have arisen where the specification has asked for a certain percentage elongation on test piece 
“C.” which requires a gauge length of four times the square root of the area. If the section of the tube 
prohibits this requirement, a machined strip may be taken, its sectional area determined, and a gauge 
length marked on it equal to four times the square root of the area thus determined, 


In these particular cases, which referred to tubes for a Loeffler boiler installation, the choice of test 
piece “©.” (British Standard test piece “F”) seemed anomalous when the more definite milled strip 
(Test piece A”), or the plugged tube test might have been substituted, as was in fact found necessary. 


With no previous experience of tube inspection, a surveyor may be at a loss to decide what limits of 
tensile strength and elongation are required by the Society for tests on tubes for water tube boilers. 
Since provision is made for tests in billet form only, one has to apply either these material limits of 28 
tons maximum, and 30 per cent elongation on test piece “,” or the limits for solid drawn steam and feed 
pipes of 28 tons maximum and 20 per cent on 8 ins. 


The latter elongation is certainly not a figure for ductility applicable to tubes for water tube boilers 
or more particularly for plain carbon cold-drawn superheater’ tubes, which may be subject to welding, 
and which come in the category of those boiler tubes. The careful annealing to which good class work 
is subjected, generally ensures at least 30 per cent elongation on a plugged tube in practice, but for the 
occasional doubtful cases a black and white ruling would form a basis for the exercise of the surveyor’s 
discretion. 


GavGina.—Uneven wall thickness, readily seen by the eye, occurs more particularly in hot-finished 
tubes. Limits of thickness tolerance are generally specified, and in some cases a go and not-go gauge is 
provided. - Care should be taken to check the swelled ends of tubes so designed, not only for concentricity 
of the swell with the tube body, but also for excessive thinning down. 


Specification tolerances in this respect are generally worded as follows :—* Thickness may be reduced 
or increased, under or over the actual thickness of the tubes, by an amount strictly in proportion to the 
percentage of such swelling or reducing.” 


In most cases, the tube is rolled thicker in the body to allow for this reduction in section during 
the swelling operation. A typical case is that of a plain smoke tube 2} ins. x 10 gauge, swelled to 
2% ins. at one end. There is almost invariably a reduction of about one gauge, or twelve thousandths in 
the tube wall at the swelled end. Thus, where the percentage increase in diameter is 11 per cent, the 
percentage thinning on nominal wall thickness is about 94 per cent. 


20 


This tube, with a hypothetical internal pressure of 300 Ib. per sq. in., and neglecting axial and 
temperature stresses would be subjected at the hody to a stress of about 2,300 Lb. per sq. in. considered as 
a thin cylinder. Under the same conditions the swelled end at 11 gauge would be stressed to 3,000 Ib. 
per sq. in. If the factor of safety based on the elastic limit was originally 2} for the 10 gange tube, the 
effect of reducing the thickness to 11 gauge would reduce the factor of safety to a little less than 2 


Although expanding into the tube plate may cause a further reduction in thickness, this is counter- 
balanced by the support offered by the plate, and one has to consider only the short length of the swell 
adjacent to the tube plate in conjunction with the possibility of corrosion and erosion in service. 


It may be of interest to record that after gauging a large number of expanded test pieces, which are, 
of course, drift or roller expanded in the cold ‘condition and without radial support, it was found that 
between the limits of 6 gauge and 9 gauge the average reduction in thickness was 20 thousandths; and 
over 9 gauge the corresponding average reduction was 13 thousandths, or broadly speaking, one gauge. 


Hypravnic Trsrina.—lt is interesting to consider that among the various tests to which tubes are 
subjected, the hydraulic test is the only procedure which stresses the material within the elastic limit 
across longitudinal planes, thus corresponding to the hoop stresses occasioned in service. In practice, 
the stress induced is a complex one, as in order to maintain water- tightness at the tube ends, a state of 
initial compression is produced in the tubes by the headers of the test bench. 


It is impossible for surveyors to witness an hydraulic test on every tube, and whilst the Rules indicate 
the acceptance of a manufacturer's certificate, it is probably understood that the testing of a small 
percentage of each order shall be witnessed by the surveyor. The very rare occurrence of a failure under 
this test may tend to some apathy in this respect, and it is regretted that the speed with which the tubes 
pass through the bench does not make for a very thorough practice. 


The author witnessed, on one occasion, the hydraulic testing of some bends to a stipulated pressure 
of 1,000 lb. per sq. in., where the belt-driven water pump was not fitted with a pressure vessel, and the 
gauge pointer oscillated between zero and some 1,200 lb. at each stroke of the ram. In this instance, 
the tubes must have been stressed momentarily considerably above the test pressure by reason of the 
dynamic effect produced. Fortunately, such primitive methods are met with infrequently, and the 
accumulator system is more general practice. 


It is suggested that the hydraulic test loses much of its effectiveness if the tube is not hammered. 
Inner surface inclusions of slag rolled into the tube wall, or of scale picked up by the piercing plug may 
escape notice, particularly in a hot-finished specimen, but may be dislodged by the vibration produced by 
a hammer blow. 


The hydraulic testing of tube elements expanded into tube plates and contained in a shell is 
sometimes a problem. The low pressure shell test is straightforward, but when the tubes are tested with 
the end covers, a slight leakage is not readily apparent through the shell door or flanges. 


In such cases it is recommended that one shell opening be placed vertically, and that its blank flange 
should have a short length of small diameter tube entered into it. The shell may then be filled until the 
water level is flush with the top of the small tube. A small amount of water may be displaced by initial 
expansion of the tube elements, but after a few moments any leakage either of the tubes themselves or at 
the tube plates will become apparent by a steady displacement from the small tube. 


One foreman with whom the author has been associated, has brazed an indicator of this type into one 
of the standard screwed adaptors for which most test flanges are drilled and tapped. Perhaps one of our 
colleagues can suggest a refinement of this idea whereby it may be ascertained which particular tube, if any, 
is the “culprit i in cases of leakage. 


A final remark which might have been included under the heading of inspection, concerns the 
opinion which has been expressed more than once that many tubes, in particular external pressure tubes, 
are examined at the time of their being worked into the boilers and that in consequence inspection at the 
tube works should take place in some lesser degree. 


A surveyor at the boiler shop has neither the time nor the opportunity to examine every tube ji 
detail, and the few black sheep that may accompany any batch of tubes may easily escape his notice if we 
detected at the tube works. If the customer asks for a definite inspection at the tube works, probably 
with the foregoing remark in mind, it is felt that there can be no two points of view to be considered. 


21 


Reference has been made to thickness of tubes in terms of standard gauges in many instances in this 
paper. A table is appended below for reference. 


S.W.G Inches. S.W.G. Inches. S.W.G. Inches. 
15 ‘O72 10 | 128 | 5 212 
| | 
4 O80 | ) | W44 | A 232 
13 | “O92 ! 5 “160 3 “202 
12 | "104 ft 176 2 276 
11 | "116 | 6 "192 I "300 | 
\| | 


In conclusion the author would like to record his thanks to the officials of the local tube works for 
their interest and assistance, in particular to Dr. Jenkin of Tube Investments, Ld., for dealing with a 
host of questions ; and to Mr. W. D. Heck for his helpful criticism and advice. 


APPENDIX. 


Tur Drescher PRrocess.—Since submitting the manuscript of this paper, the author has carried 
out the inspection of hot-finished tubes manufactured by the Diescher Process, and such particulars of 
the plant and process as are available are now included. This process is a modern development, and the 
first licences under the original German patent were secured by the Babcock & Wilcox Company of 
Pennsylvania, whose plant commenced operations in 1933. 

The plant of the English Seamless Tube Company of Birmingham was installed two years ago. 
This plant is remarkably simple, and consists of a piercing mill and an elongator; the latter combining 
the usual operations of rolling and reeling in one operation. 


Keo 


The range of tubes may be taken as 8} ins. ofd to 14 ins. o/d, and thicknesses from 3 in. down to 
12 gauge. A typical case is as follows :— 
Billet 2} ins. x 8 ft. 6 ins. 
Pierced hollow 2 ins. x ,°s in. x 9 ft. 0 ins. 
Finished tube 2} ins. x 8G. x 17 ft. 0 ins. 


The operation is a rapid one, and the tubes leave the mill for the cooling racks at a temperature 
corresponding to normal annealing temperatures. The plant consists of a piercing mill and an elongator, 


Prercinc Mini.—This mill comprises a pair of skew rolls similar in form and principle to the 
Stiefel piercing discs, which effect the “ breaking down,” expanding and forward movement of the billet. 
The billet is guided above and below by large diameter discs, haying semi-circular grooves conforming 
to the shape of the billet. ‘These discs are free to rotate, and are certainly an improvement on the flat 
guide bars of the Stiefel piercer. 

An opposing mandrel and plug are employed, but with one important distinction. The mandrel, 
which is water-cooled internally, is free to rotate with the billet, and terminates at the back end in a 
heayy roller thrust which, it is understood, may sustain a load of nine tons. The plug or head is a loose 
fit in the mandrel, and falls off automatically on completion of the piercing. 


From the piercing mill, the hollow is transferred by skids to the mandrel table, where a rolling 
mandrel about 4}; in. to } in. smaller in diameter than the bore of the hollow, is inserted by means of 
pinch rolls. The hollow, with the rolling mandrel within it, is then skidded to the elongator table, and 
pinch rolls feed it into the elongator. 


22 


Enoneator.—The barrel-shaped working rolls of the Elongator are similar to those of a reeling 
machine in most respects. They are about 20 ins. in diameter, revolve in the same sense at approximately 
800 ft. per minute, and their axes are inclined in a horizontal plane at about 6 degrees. Their function 
is to determine the wall thickness of the tube, for which purpose they are capable of adjustment. 


Since the rolling mandrel is free to rotate with the tube, and is not secured at either end, the rolls 
“squeeze” the tube material on to this mandrel, and the relative inclination of their axes produces the 
forward movement, extending the tube over the mandrel within it. 


Fig. Al is an end sectional elevation showing the two working rolls and the rotating guide discs 
above and below. The tube is shown in disproportionately heavy section to illustrate the tendency to 
assume an elliptical shape at the point of greatest “pinch” of the main rolls. This tendency is 
corrected by the guide discs, which, as may be seen by the small section at the foot of the figure, have a 
“leading ” edge to their working surface. 

These rolls or discs, of about 30 in. diameter establish the tube diameter, and are rotated 
independently of the working rolls in sense so as to increase the speed of the tube, over and above the 
speed of advance effected by the working rolls. These discs are, of course, capable of individual adjust- 
ment, arranged in such a way that their centre line is maintained at the intersection of the axes of the 
working rolls. Their peripheral grooves are designed to correspond to the elliptical tube section during 
rolling. Although the mandrel within the tube advances and also rotates, it does so in a lesser degree 
than the tube itself, and it is claimed that the resulting “slip” gives the tube a comparatively good 
internal finish. 

Experiments with eccentric hollows have proved that the Elongator provides automatic correction 
of inequalities in wall thickness. The longitudinal rolling ratio in the Elongating operation may be as 
much as 45 to 1. It has been mentioned that 1% ins. is roughly a minimum size ‘for tubes made by the 
Diescher process, and a reducing mill is employed when any further reduction in diameter is required. 


The plant at the English Seamless Tube Company’s works includes a reducing mill of the type 
which has alternate horizontal and vertical pairs of rolls, of which every other pair is independently 
driven by electric motor, and is capable of independent adjustment. The intermediate pairs of rolls are 
free to rotate as “idlers.” It is stated that rolled tubes of 1% in. diameter have been reduced to @ in. 
diameter on this mill, but information as to the degree of variation from a truly circular bore in such 


cases was not offered. 


mie 


EEE 


Fig 1. MANNESMANN PIERCING MILL 
DIAGRAMMATIC PLAN VIEW 


aan ELEVATION — REDUCED SIZE 


ES SHOWING 


TOP STEADY ROLL & UNDER GUIDE 
Fre. 2 


ELEVATION 
~ SHOWING - 
OTIEFEL Dise PIERCER. Tor ¢ Bottom Guides 


PuAN VIEW 


Guoe Dise 
flosustine Screws. 


FLexiBLe Courune. 


Fie. AI. 


Rotatiwe Guwe Disc. 


| 


SEcTION of Guioe Disc. 


DIAGRAMMATIC END ELEVATION Nore =~ To tustaaré The 


Guioe Disc Contour, THE SEcTioweD 


OF 


DIESCHER_ ELONGATOR HoLLow 1S SHOWN AT TRE ¢ 


OF Tre Two Discs. 


Hp 


NAN 
a 


LL EASY 
\ SS 


ZINE | RQESNY. 
WZ) 7 LANG'S 


\ 
ee 


ZZ 


HYDRAULIC 


PIERCING PRESS 


Diagram of Push Bencn Process. 


PILGER ROLLS 
DIAGRAMMATIC PLAN 


Sectiovat Evevatiow Ar X-X 


Fig. 9, 


DiaGRAM OF Corp DRAWING 
OPERATION 
| 
Part Sectionac DiaGRan 
OF 
Rotary Swacinc 
_Macnine 


Boe 
2 


Lik 
ss \ es ‘\ 


ROTATING ~~ 


MEMBER 


tig. 11. 


DIAGRAM of CoRRUGATING 


i RINCIPLE. 


STAGES IN THIMBLE TuBE FABRICATION 


rile 


Ee 
ED | 


Hs 
Ean f 


eal 


~ 
oWMU MN O WNW A wUH 


- wp 
wre 


- RF FF Fe 
@ONA wm F 


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o 8 


Fig. +3. 


DIAGRAMMATIC SKETCH OF WELDLESS 


STEEL TUBE MILL LAYOUT 


Stee. Stock. 

Coro BicteT Saw 
Bitver Heating FURNACE. 
PieRcinc MACHINE, 


Picerk Mur 

Royreo Tesés on Cooiinc Racns 
TAGGING 

Picxce Bosn Repeat Items 7170/3 
WATER DORH ts. Aeéononwed Wire 
Deving N° oF Passes 
LuBRICATING 

DRAWING 


ANNEALING FURNACE. 

(For Inter Pass Worx & Fiva, Hear Teeatmenr) 
COOLING Racks 

STRAIGHTENING. 

EXAMINING 

CuTTING OFF 

EXAMINING AFTER Finan Hear TREATMENT 
FINAL INSPECTION 


DesParTcH 


| a A i aan | f ie | 
Pitan eh fe al 


® 


DISCUSSION ON G. T. CHAMPNESS’S PAPER 


ON 


SEAMLESS STEEL TUBES. 


D. GEMMELL (London), 

Some 13 or 14 years have elapsed since my surveying duties took me to the tube makers’ 
works, and I have no doubt that the processes of manufacture have been greatly improved 
during that time. The field for seamless steel tubes has increased enormously in recent years 
and their reliability in service is beyond question, 

Large quantities of these tubes are used in connection with the manufacture of refriger- 
ating machinery and one of the largest manufacturers in this branch of engineering has informed 
me that they use an average of about four million feet of solid drawn tubing in one year and 
that this figure has probably been greatly exceeded in the past vear. Some of. the large 
refrigerated vessels trading to the Argentine have as much as 80 miles of solid drawn tubing 
in their refrigerating installations. 

With regard to the piercing of square billets in a cylindrical die, a considerable amount of 
seale must be cracked off into the four segmental spaces between the sides of the billet and the 
walls of the die, and this seale will be erushed into the surface of the billet. The indents 
made by the scale may be considerable and I would like to know if these surface marks have 
any effect upon the finished tube. The same query would apply to chipping, gouging or 
burning out surface defects. 

In the pickling process a rust forms upon the tubes and it used to be considered that this 
was beneficial to the drawing operation. Defeets in the tubes are revealed after pickling and 
a percentage rejected at this stage. Can the author tell us whether the percentage of tubes 
rejected after each stage of anne: ling and pickling varies towards the final draw? 

Reference has been made towards the manner in which the test pieces are marked off on the 
selected tube and that the test piece on the end of. the tube should be reserved for the 
expanding test. Would the author explain the reason for this? At the time when I was 
inspecting tubes in the maker’s works. I frequently found surface lines revealed in the 
crushing tests and also in the flattening and bend tests. Will the author tell us if in modern 
manufacture these lines have been eliminated? 

The paper will give those Surveyors who have no opportunity of visiting the tube maker's 
works some idea of the processes involved, and it. has certainly revived my own memories of 
the years I spent visiting the factories in the Birmingham district, 


D. R. Watsurn (London), 

I should like to join in congratulating the author for his excellent paper which, I feel 
sure, will be of considerable interest to all who have not had the opportunity of studying the 
actual process of tube manufacture at the tube works. On page 11, the author, after diseussine 
the two methods of cooline with regard to the heat treatment of the tubes, viz. : furnace cooling 
over a period of six hours and floor cooling, states that it is probably immaterial which method 
is employed. 

From a metallurgieal standpoint, I think the influence would be rather marked as, on 
cooling low percentage carbon steel from temperatures of 880-950 degrees C., ferrite is liberated 
in an amount proportional to the slowness of cooling up to the maximum amount consistent 
with the carbon content of the steel, and the austenite is converted into well developed pearlite. 


This liberation of the ferrite definitely coarsens the structure, and if the rate of cooling is very 
slow throughout the range 700-650 degrees C. there is the danger of forming globular pearlite, 
thereby seriously affecting the tensile strength of the steel; this may result in failure in 
service. 

With floor cooling a finer structure and a definite increase in the tensile strength is obtained 
as the author states, but I would suggest the statement that this increase is accompanied by a 
corresponding reduction in elongation is rating this percentage too high and that the elongation 
is actually not greatly decreased. 

Though furnace cooling may increase slightly the creep resisting properties of the tubes, 
it appears to me, however, that floor cooling has distinct advantages over furnace cooling and 
I would appreciate the author’s further remarks on this subject, also, whether “six hours’? may 
be regarded as the time generally adopted by the tube manufacturers with furnace cooling. 

Then, again, further down the page, the author mentions a form of low temperature 
annealing, below the AC1 point, of cold drawn tubes, therefore, as no re-erystallisation occurs 
at this temperature, the tendeney will be to reproduce the original unannealed structure on 
cooling, unless the “blueing”’ is a process carried out after the tubes have been normalised in 
the usual way. I would appreciate the author’s remarks on this point also. 

In the following paragraph an instance is quoted where “scaled” boiler tubes were preferred 
to those ‘“‘seale free.” . 

It would be of interest if the author could give further particulars regarding the condi- 
tions of service for which these tubes were intended, viz.: whether subjected to high steam 
temperatures and, or, highly corrosive gases, and further, are the advantages claimed such as 
would warrant the acceptance of scale covered tubes?—having in mind the examination of the 
tubes for defeets and the cracking of the seale in service. 

The author’s description of the process employed in the manufacture of thimble tubes is 
very interesting, and I will be glad to know whether there is another process employed in the 
manufacture of tubes of this type, viz.: tubes pressed from the solid plate. 

Though the paper deals exclusively with the manufacture of tubes, I trust a digression 
may be allowed. What precautions are taken to prevent the corrosion of tubes carried in stock? 
In asking this question I have in mind an instance in my experience when replacing several 
faulty tubes in a boiler. 

On taking the requisite spares from the racks in the stokehold, these tubes were found to 
be very badly corroded, so much so that by bumping them endwise thick flakes of scale fell 
to the plates—in fact, many of the tubes were unfit for use. In this direction I would recom- 
mend that all spare tubes to be carried aboard vessels be coated with a suitable anti-corrosive 
paint or sealed at the ends and containing a little lime. 


L. H. F. Youne (London). 

Comparing the two principal methods of producing the finished tube, although the two 
processes are quite distinet the final result appears to be the same, the quality of the tube being 
as good in the one case as in the other. The piercing of the billet for the Pilger Mill is an 
operation requiring more time than piercing by means of a hydraulic press for the Push 
Bench method, so that by the latter method there is not so much chance of heat being lost 
during the process as in the former. The number of rejects from the hydraulie press might 
therefore be expected to be less than from the other process, and this seems to be the case. 

On the other hand, whereas the action of the Pilger Mill is of the nature of forging, 
although it must be admitted to be rather drastic treatment, the Push Bench method might be 
said to be a mild approach to the process of extruding. Extruded metal proper, such as wire, 
is produced in one pass, while tubes are, of course, subjected to several passes and several 
heats. Tubes produced by either process are equally good; but is this the case before they 
undergo final heat treatment? If such is not the case, then it must be presumed that a great 
deal depends on the efficacy of the final heat treatment. 


3 


The Push Bench process is usually employed for the manufacture of air receivers, and no 
doubt this is found the more convenient for large tubes. Swaging and expanding processes 
are referred to on page 13. It is concluded that this refers to the tube ends or to a certain 
portion of the length of the tube. 


P. Kerrscuer (Prague). 


I wish to congratulate Mr. Champness on his excellent and instructive paper, which is a 
valuable addition to the Transactions, and there is only one point on which TI should like to 
make a few remarks. In the last paragraph of page 18 «and on page 19 of his paper 
Mr. Champness deals with the subject of percentage clongation of specimens cut from the 
finished tubes. 

From the results of a great number of tests I have plotted the curves shown, indieatine 
the variations of the percentage elongation for different ratios “gauge length: square 
root of the area of cross section.” It is obvious therefrom that a truly representative and 
comparable figure of elongation ean solely be obtained when a standard ratio “gauge length : 
V Area” is adopted in a similar way as for the Society's standard test pieces for forgings and 
castings, where the gauge leneth is four times the square root of the area of cross section. 


On the Continent a sharp distinction is being made between “Standard Test Piece” and 
“Standard Ratio Test Piece (Proportionalstab),” the latter having no definite cross section or 
definite gauge length, but a standard ratio of cross section and gauge length, and has been 
used for decades for specimens taken from finished steel tubes. For instance, in the German 
“Regulations for Water Tubes and Stay Tubes” the standard ratio is 113 V Area (corres- 
ponding to a gauge length ten times the diameter of circular test pieces) is stipulated for all 
tensile specimens cut from finished tubes, either as strips or test lengths, viz. :— 


Ultimate Tensile Strength. Minimum Elongation 11.8 \/ Area. | 
22-2 to 28-6 tons per sq. in. 20 per cent 
28:6 to 35-0 * 17 re 


and thus it is possible to provide a reasonable width of the test piece for any size or thick- 
ness of tubes, and to obtain a truly representative figure of elongation, whereas with strips 
a standard gauge length of eight inches in the ease of lesser thickness and limitations of 
width due to curvature may correspond to anything up to 35 x ¥ Area, and accordingly it will 
be difficult to obtain the required figure of elongation though the material may be of good and 
ductile quality. 

For instance, Standard Test Pieces “A” eut from finished tubes made of the same cast of 
steel will, due to variations in the sectional area, give approximately the following figures of 
elongation :— 


Dimensions of Test Gauge Length 8 inches, . . 
a ; : Elongation. 
Pieces, corresponding to:— 
gin. x 1} ins. 10/5 x V Area 24 per cent 
13/64 in. x 25/32 in. 20 x V Area 17 per cent 


5/64 in. x 19/32 in. 35 x V Area 13 per cent 


Especially for non-marine work to be tested in accordance with the Society’s Rules, 
unusual sizes and thicknesses are met with for which it is difficult to apply the standard 
eauge length of eight inches. There are well-known firms on the Continent ordering tubes for 
power plants in England and elsewhere to be tested by this Society’s Surveyors, but in _accor- 
danee with the German “Regulations,” and when asking for the reason I have been told that 
the latter are easily applicable to any kind of tubes, even alloyed steel tubes for high pressure 
and temperature, and that the figure of elongation obtained from “Standard Ratio Test 
Pieces” is a better criterion of the ductility of the material. 

Perhaps I must apologise for being elementary when mentioning that the variation of the 
percentage elongation for different ratios of eross section and gauge length is due to the elonga- 
tion caused by the reduction in area, whieh is added to the “basie” elongation of shorter or 
longer gauge lengths. It is obvious that the influence of the reduction in area is predominating 
for short gauge lengths, and nearly disappears for long gauge lengths. The “basic” elongation 
is the percentage elongation prior to the commencement of contraction, and is practically 
uniform for any gauge length. For the material in question it will not be less than 13 per 
cent, and can be easily determined by suddenly interrupting and taking the test piece out of 
the testing machine when the peak load has just been attained, as up to this point the test 
piece is stretehed uniformly without any local contraction. 

Due to the irregularities in thickness and rougher surface of test lengths from hot rolled 
tubes, the percentage elongation is inferior to that obtained from cold drawn test lengths; it is 
still less for strips in the eurved condition, due to the stress concentration at the sharp inside 
edges causing rupture before reduction in area has been fully developed, especially when the 
width is more than four times the thickness. For transverse test pieces, even when st raightened 
hot and annealed, the German “Reeulations” demand two per cent less elongation than for 
longitudinal tests. 

Summarising, I am of the opinion that a standard ratio “Gauge Length: ¥ Area” (prefer- 
ably 11.3) should be adopted for tests on finished steel tubes. 


H. McCririck (Birmingham). 

Mr. Champness has put before the Association a most interesting and instructive paper on 
present day manufacturing methods used in the production of unlimited miles of seamless steel 
tubes, which form the connecting links in so many sect ions of this century’s civilisation. 

In dealing with the quality of material used for tubes which most frequently come under 
our inspection, no mention is made regarding quality except that it is plain carbon quality with 
a carbon content ranging from -10 per cent to 20 per cent and that sulphur and phosphorus are 
specified not to exceed 04 per cent and manganese varying between 3 per cent and -7 per 
cent: this steel to comply with our requirements must be made by the open hearth process, 
either acid or basie open hearth steel can be used. I think it is generally found that basic steel 
with its slightly lower tensile strength in relation to an acid steel of the usual composition is 
considered more suitable for tube billets. 

In view of the large Bessemer steel plant which has recently been brought into operation in 
this country, principally for the manufacture of steel strip for welded tubes, as I understand 
part of this steel has been used for the supply of billets for the manufacture of hot drawn steel 
tubes, I think it would be of interest generally if the author could give his views on the use of 
Bessemer Steel in the manufacture of such tubes, as it is probable in the near future we may 
be ealled upon to examine and accept same. 

Considerable variation in the quality of Bessemer Steel is found, which I understand to a 
certain extent depends on the ore from which it is made, but the question of the inereased 
amount of impurities found in Bessemer Steel and the effect of the drawing-out qualities 
of the steel due to these impurities has, I think, to be considered when recommending its 
adoption for certain grades of tubes. 


eo 


Under the heading of methods of reducing, mention is only made of the fixed or floating 
solid die being used on the draw bench. It has come to my knowledge that a further develop- 
ment of the process, which has a series of roller dies, has been introduced both in this country 
and the Continent with marked success for hot drawn tubes. The cost of manufacture has 
heen considerably reduced, output speeded up and a tube produced with a much smaller degree 
of wall thickness variation than found with the fixed die method of tube drawing. On page 2 
the drilling of billet is mentioned; this, I understand, is still practised occasionally, but in 
view of the time involved in the operation and the possibility of producing tube billets free from 
central segregations, | cannot think that drilling will find much favour now. 

Under the heading of “tapered tubes for waste heat boilers” I think mention ought to be 
made of the successful manufacture of these tubes by pressing same from flat plates. Special 
quality material is, of course, called for, and the tubes are annealed between each pass. Thimble 
tubes with a spherical end are now being used for certain types of economisers. These are 
manufactured in pairs, a piece of tube equal to two lengths of thimble tubes is heated at the 
centre and eressed down with a power hammer, similar to the method employed with certain 
types of air receiver ends. The centre section of the tube is cressed in almost solid. The 
tube is then parted at the centre and the small opening at the junction is sealed up by 
electric welding. In conclusion, | would like to congratulate the anthor on placing before the 
Association a very detailed paper on tube manufacture, which I am sure must have been 
weleomed by many who have not had the opportunity of visiting a modern tube works. 


D. Mckeniar (Glasgow). 

I wish to congratulate Mr. Champness on his excellent paper. On page 8 the author remarks 
that he would be interested to hear from a colleague the reasons for the popularity of the 
“Automatie Process” in the Glasgow district. May I submit three reasons :— 

1. The Automatie Process enables the manufacturer to produce light gauge tubes 
with a more even surface. The writer noted this when on the subject of ground ends as 
required on seamless steel tubes. On account of continuous bumping with the Pilger 
Process there is a tendency to cause a waviness on the surface and this would tend to 
cause tubes to be “under gauge” at certain points. 

2. Another important point is the rapidity of action with the Automatie Process. 
When working light gauge tubes the tubes get cold sooner and the swift aetion of this 
process retains the heat during the operation. 

3. Adaptability for changing size and thickness of tubes. With the Automatic 
Process this can be done in a very short time and yarious diameters of tubes can be 
done with very little heavy labour employed. 

Referring to page 7 of your paper, may I state that the machine in Glasgow “involves 
the use of rolls having a number of semi-circular grooves of approximately similar size’’ not 
“of suecessively decreasing sizes.” 

Referring to page 17 of your paper, is vour reason for having the expanding test on the 
end of the tube on account of this part of the tube being expanded into the boiler in’ the 
ease of boiler tubes? 

Again, would it not be advisable to have the expanding test nearer the middle of the tube 
as this would give the expanding test of the tube in its normal state? 


Outline of Automatic Process.—Billets are taken to cold saw and sawn or sheared the 
required length. They are then placed in furnace and gradually heated to approximately 
1000 degrees C. and from there to Rotary Piereing Mill. From there they are taken to the 
Automatic Mill. This particular machine will take tubes down to 12 w.g. and the same tube 
will go through the one pass twice, being put in the second time at a different position from 
the first time, this being done to take away any overthiekness on the tubes at two places caused 


6 


by the collars coming together. The tube is then put through the Polishing Mill, this being 
done to mangle the walls to remove any scores. Plugs are used for both the Automatie and 
Polishing Mills. Finally, the tube is put through the Sizing Mill by means of rollers. This 
will fix the outside diameter of the tube. They are next taken to the cooling racks and then 
tested for length and finally cropped as required. (See diagram.) 

Automatic Mill.—In rolling methods the usual practice is to roll by a few passes over a 
mandrel. In the Automatic Mill the completely pierced hollow bloom is forced against the 
rolls behind which is placed a mandrel held on a rigid mandrel bar fixed in a rack behind 
the mill. When the tube is through the mill the top roll lifts and an auxiliary roll engages 
the rolled bloom and throws it back through the opened rolls to the delivery side of the mill. 

Two or three passes are usually sufficient—if the hollow bloom size has been correctly 
chosen—to produce the finished tube. Tubes afterwards pass to a pélishing mill in which the 
diameter is increased slightly over a mandrel. 


K. L. M. Porncer (Paris). 

I have read with much interest your paper on “Seamless Steel Tubes.” May I offer a few 
remarks and inquire for further information? 

On page 4 you give the dimensions of the finished products as compared with the initial 
billet. When working the figures corresponding to the weights or volumes of the various items 
by the formulae d?L for the billets and 4t(d-t)L for the hollows and tubes 

d=external diameter in inches. 
lL, =leneth in inches. 
t =thickness in inches. 


I found the following :— 


dL 4t (d-t)L 

Hot billet - - - - - 3hims. x 20imns. - - - - - - - 245 - - 
Pierced billet - - - - 3ins. x gin. x 40 ins. Bile on o= - - 240 
Rolled hollow - - - - Ilgins. x -192ims. x 14ft. 6ins. - - - - 225 

| 1d ins. x -202 ins. x 22 ft. Ging. - - - - 202 
Hot finished - - - 1d ins. X 202 ins. x 20ft. - - - - - - 220 

( 1zins. x -192ins. x 14 ft. 6ins. - - - = 295 
Cold drawn - - - - Ilins. X -116ins. x 45 ft. Gims. - - - - 286 


The later figure indicates some error in the dimensions of the cold drawn example; for 


instanee, is the length (45 ft. 6 ins.) not to be amended to 35 ft. 6 ins., which gives about 225? 


: : : : : : 220 
Taking 220 as the mean in the various cases it appears that the efficiency is about 245 


= 90 per cent. 


On page 21 “appendix,” the same calculations give : 


Biletest2= ac Si bs oe Daina xb se Gane te Rt | SUS ODI 
Piereed hollow - - - - 2#ins. x -312ins. x 9 ft. tee a het a OU 
Finished tube - - - - 24ins. x -160ins. x 17ft. - - - - - 272 


The volume of the billet is not in accordance with that of the finished product. 

I may say that the various processes in use in France are the same as those described in 
your paper, except as regards the so-called “Diescher process,” which is a new one to me. 

The “Elongator” appears to he a very interesting device, and I should be very much obliged 
to have the following additional information about it. 


(a) What are the maximum diameters of hollows the elongator is capable of dealing 
with? 


7 


(b) Is the same set of working rolls used whatever be the diameter of the hollow? 
Same question for the guide dises? 


(c) Is the elongation of the hollow and the designed thickness of the finished tube 
obtained in several passes? For instance, how many passes are necessary to obtain the 
maximum clongation ratio +5 to 1 indicated by you? 


(d) I suppose that various mandrels are necessary according to the size of the 
hollows, the thickness of the tube, ete. 

(c) Are there special precautions to be taken to assure an easy entrance of the hollow 
in the elongator? 

(f) From the speed of 800 ft. per minute indicated on page 22, I assume that the 
longitudinal speed of advance is about 80 ft. per minute, so that the time necessary for 
dealing with a tube, say 40 ft. length, in the elongator is about 30 seconds. Is that correct? 


I have heard of a German process obtaining seamless steel tubes in a manner similar to 
that by which lead tubes are fabricated. The apparatus used is a vertical extrusion press of 
the Krupp type, with special dies of chromium steel. In the first operation, a small mandrel 
pierees the billet, and is held steady in its final position. In the second operation a piston, 
sliding over the mandrel, descends on the billet and forees it through the annular space formed 
by the die and the mandrel. Is there any installation of this type in your country? 


REPLY BY THE AUTHOR. 


Mr, Gemmell’s astronomical figures of the amount of solid drawn tubing in use in refri- 
gerated vessels show that the subject of the paper must be of great interest to him. It is a 
pleasure to receive a contribution from one who has been associated closely with the Birmine- 
ham district. 

The question of seale accumulating between the sides of the billet and the walls of the 
cylinder of the vertical piercing press does not seem to arise in practice. As the plug enters the 
billet the seale loosens at once, and as this seale falls more quickly that the plug deseends, it 
will accumulate at the bottom of the eyvlinder. 


This cannot be verified in practice, but it is suggested that this explanation is a likely one, 
as the pierced billet, when withdrawn, is generally seale free. Even small amounts of seale 
can, of course, readily be seen, since they are not properly in metallic contaet with the billet 
surface and are consequently at a lower temperature. Any depressions caused by ehipping 
or gouging of the cold billet are eliminated by the forgine effect against the eylinder wall, 
particularly in the final stage of the operation, when some vertical displacement takes place. 
It is generally accepted that an oxide layer on the surface of a pickled tube assists the cold 
drawing operation. 

The author considers that the end of the tube should be reserved for the expanding 
test for the following reasons: Firstly, the end of a hot finished tube is ragged, like the 
edge of a rolled plate, and is generally cropped for a length of about 14 ins. Insufficient 
cropping would be shown up by the expanding test. Secondly, if a boiler tube has to be 
expanded into a tube or drum it seems logical to ensure that the selected test tubes shall be 
capable of withstanding this deformation. And, finally, in tubes pierced by the Ehrhardt 
process, central segregation, if any, tends to accumulate at the end or bottom of the “bottle.” 
This end is cropped, and a test on the tube end thus formed may be instructive. 


With regard to pickling and the detection of defects, this operation certainly may reveal 
trouble which would otherwise be covered by seale. But, from a number of enquirics, the 
author is given to understand that surface inspection between draw bench passes is rarely 
performed, apart from experimental and research work. Moreover, in the few eases whieh 


8 


have been submitted, the inspection has taken place on the tubes in the bright state straight 
from the second or third pass. This procedure was, in fact, carried out in the case of many 
of the tubes for the boilers of the “Queen Mary.” 

Mr. Gemmell mentions surface lines revealed in the various deformation tests. The 
existence of such lines depends largely upon the process of manufacture; tubes made by the 
Diescher process, for example, being remarkably free from any evidence of such lines. Scores 
occasioned by the rotary. piercing plug, or by abrasive particles on the drawbench dies and 
plug, are still fairly frequent and are readily shown up in the flattening and erushing tests. 
The most consistent cases of lines are probably those found in tubes made by the automatic 
process, to which reference is made in the author’s reply to Mr. MeKellar. Well defined sur- 
face lines should not be confused with the fine “eracks” which are to be seen on many test 
specimens, and which have been discussed at the bottom of page 15. 

Mr. Walburn may rest assured that there is little likelihood of spheroidisation with the 
general methods of cooling tubes employed. The author’s final remark anent air or retarded 
cooling was based on a consideration of the small masses involved, and the small carbon con- 
tents under consideration. The furnace cooling of small masses, when retardation is not very 
pronounced, will often produce results equivalent to the air cooling of larger masses. But 
“Box” annealing of tubes is hardly comparable with the practice of slow cooling of forgings 
in the furnace. 

The author should have made it clear that when the period of saturation is complete the 
gas is shut off and the “Boxes” are removed from the furnace. Even when sealed in the boxes 
the tubes will cool rapidly in comparison with the large mass of a forging. The walls of the 
box are probably not more than ~ in. in thickness, with a correspondingly small temperature 
eradient. In addition, the tubes are well packed, providing conditions for efficient heat con- 
duction to and radiation from the box surface. 

The figure of “six hours” should not be taken as a representative time for cooling. It is 
to be regretted that the case referred to was a specifie one, where the tubes were withdrawn 
from their boxes after that period. In practice, in order to avoid congestion of the cooling 
bays, the tubes are removed as soon as they are cool enough to handle. Nickel alloy tubes, 
with which this paper is hardly concerned, are frequently held in the “dead” furnace for 
many hours before removal, this being done in order to obtain the necessary ductility. In 
further reference to slow cooling in steel containing about -15 per cent carbon the percentage 
of cementite (and therefore pearlite) is so small that its influence upon the grain size is not 
pronounced. In addition, it should not be necessary to point out that grain size, per se, is 
primarily determined by the saturation temperature and period. 

With regard to the form of heat treatment termed “Blueing,” which, as Mr. Walburn 
rightly points out, can involve no reerystallisation, this process is employed in lieu of 
normalising when a high yield is required. A typical example is that of Aircraft Tubing, 
where the specification may call for a 2 per cent proof stress of 30 tons and a maximum stress 
of 35 tons. It is agreed that the expression “corresponding reduction” in elongation with 
inerease in tensile strength due to air cooling is misleading, if interpreted in the sense of 
“proportional,” as Mr. Walburn suggests. It is considered that typical figures for similar 
specimens of small mass, of the material with which we are concerned, when furnace cooled 
and air cooled might be 22 tons with 36 per cent and 26 tons with 34 pei cent elongation. 


The author regrets that he is not in a position to give any further information regarding 
the conditions of service for which the “sealed” tubes referred to in the penultimate para- 
graph on page 11 were intended. These tubes did not come under the Society’s inspection, 
and the case was quoted during a discussion upon the effeet of furnace gases when “open” 
annealing. .Mr. Walburn’s experience of corroded tubes taken from shipboard spares is, it is 
to be hoped, a comparatively unusual one; although in the author’s experience spare smoke 
tubes have had to be disinterred from firebars and ashes on the tank tops between boilers. 


9 


Tube works practice in the ease of tubes which are not to be electro-zinced, is to coat them 
with boiled linseed oil or other suitable preservative when they are to be transported any 
considerable distance, or held in stock. In eases when eleetro-zincing has been earried out, 
and the internal surfaces are polished, the tubes are treated internally with lime and stoppered 
with wooden plugs. 


With reference to the manufacture of thimble tubes by manual forging, a process similar 
to that described by the author is a practice in the Glasgow district. It differs in so far as 
two tubes are made from one leneth of tubing, whieh is reduced at mid-leneth by dies and 
then necked. Each half is then heated at the reduced end, placed over a mandrel as in figure 
12, and closed over to form the point of the “thimble.” 


The author is indebted to his colleague, Mr. Porter, for information on the formation of 
these tubes by the “eupping” process from solid plate. As an approximate figure, tubes 
12 ins, x 2lins. x 10 ins. gauge in the body, and tapering to 1? ins. diameter are manufactured 
from dises of steel about 12 ins. diameter by ,‘, in. to 2 in. in thickness. The first operation 
is that of cupping in a manner similar to the dishing of evlindrieal boiler end plates. 


Subsequent operations consist of forcing the cupped dise through a suecession of dies, 
finally resulting in a parallel tube, solid at one end. The final operation of forming the taper 
is effected by pressing this tube into a tapered die as far as required. 


The complete process is carried out in five or six stages in the cold state, and consequently 
heat treatment between stages is necessary. 


In reply to Mr. L. F. H. Young's remarks as to the relatively few rejects from the 
hydraulie press, the author would like to suggest that this is due (a) to the rarity of eccen- 
tricity in billets from the hydraulic press, and (b) to the strenuous nature of rotary piercing. 


Defective billets from the Mannesman and Stiefel piereers owe their rejection in most 
cases either to splits or to eccentricity. 


It is probable that ‘original sin” in a billet, which is exposed by the torsional strains 
during rotary piercing, might remain undeveloped during the comparatively mild compres- 
sion effeet of vertical piercing. 


Mr. Young points out that tubes made either by the push bench or the Pilger mill are 
equally good, and asks if this statement holds good before they undergo heat treatment. 
Hot finished tubes undergo no heat treatment unless they are required less than about 1{ ins. 
diameter in the case of Pilgered tubes, and less than about 24 ins. for tubes from the push 
bench, so that tests are taken from the tubes as rolled and reeled. When draw bench passes 
are necessary, then, as Mr. Young states, the final mechanical properties of the tube are 
determined to some extent by the efficaey of the heat treatment. Mr. Young is correet in 
assuming that the remarks on page 13 refer to the reducing and expanding of a portion of 
the tube length. A typieal example is a 24 ins. x 10 ins. gauge evlindrical boiler smoke tube, 
swelled at one end to 24 ins. for about 24 ins. 


Mr. Kertseher has raised an interesting point with regard to the difficulty of assigning a 
suitable figure of percentage elongation when the dimensions of the specimen prohibit the test 
piece being taken in the specified form. The curve of elongation variations shows without 
further comment that in order to make comparable tests of different sectional areas, there 
should be a constant ratio between sectional area and gauge leneth. 


Incidentally, the test results upon which the curve is based appear to have been taken 
upon somewhat dissimilar steels, as the eurve form is not hyperbolic. The constant of 11:3 in 
the German formula, corresponding, as Mr. Kertseher states, to a gauge length of 10 x D, is 
based upon the general expression for cylindrical forms of D=118 Y A, 


10 


It is advisable to pull the tube in full section whenever possible in order to avoid the 
“stress raisers” inevitable at the edges of a milled strip, apart from the question of curvature, 
so that it is unlikely in general practice that machined test pieces of dimensions as small as 
those given in Mr. Kertscher’s Table II, will be encountered from boiler tubes or steam pipes. 


Table II evidently refers to material rather less ductile than ordinary low carbon steel. 
Mor if a typical 24in. x -128in. hot rolled tube is considered, a milled strip test on the lines 
of Mr. Kertscher’s figures, by interpolation, would suggest an elongation of about 14:5 per cent, 
whereas an average elongation figure on 8 ins. for this type of tube, pulled full section, is 
generally about 26 per cent. This example happens to be one where the Proportionalstab 
would be equivalent, as the 8 ins. gauge length corresponds to a constant of about nine. 


A typical example from Water Tube Boilers, that of a cold drawn tube 1} ins. x -128 in. 
where 35 per cent elongation on 8 ins. may be expected in the properly annealed condition 
for tests in full section, corresponds to a constant of 12-6. It appears, therefore, that German 
practice in respect of full section tests has much in common with our standard 8 inch 
leneth, but some difficulty arises in correlating 113 VY A and standard test pieces C., D. and 
EK. where V A corresponds to -5, -7075, and -866 square inches respectively. This is evident 
when it is noted that 11:3 vy A. in the ease of E, requires a gauge leneth of nearly 10 ins. 


It is unfortunate that the reduction of area, in the ease of a tube pulled full section, is 
not so speedily determined as the percentage elongation, since the former is independent of the 
variables inevitable with test pieces of varying dimensions. The combination of reduction of 
area and bend test is probably more instructive than the elongation figure per se. 


Experience shows that a minimum reduction of area of about 35 per cent for straight 
carbon steels is necessary to ensure a satisfactory 180 degrees bend, regardless of a reasonably 
high elongation figure being obtained. And since the Izod test is rarely called for in tests of 
tube material, the reduction of area is a useful criterion of the efficiency of the heat treatment 
carried out. 

There is probably no reason why good Bessemer steel, and Mr. MeCririck undoubtedly 
refers to basie Bessemer where tubes are in question, is unsuitable for steel tube manufacture 
in particular. Certainly the presence of non-ductile inclusions in steel for tube manufacture 
is to be avoided as much as possible, but one does not necessarily expect to find more non- 
metallic inclusions or segregations in basic Bessemer than in open hearth steel. The fact 
remains that in spite of the periodical fracture examinations during the Bessemer blow, one 
cannot guarantee a sound, homogeneous material with the same degree of consistency as may 
be anticipated with steel from the open hearth, where the metal is under observation for a 
comparatively long period of time. 


Excellent low earbon steel can be made by the Bessemer process, but the critical period 
of the blow is so short, and so much depends upon the human element that some lack of con- 
fidence in the continuous production of high grade steel is justifiable. When the practice is 
to transfer the Bessemer blow to an electric furnace for final refinement, there is little reason 
why the resulting steel should not be a suitable one for tubes, as for any other purpose. But 
this duplex process is by no means the usual practice, and is, perhaps, open to abuse in times 
of high pressure production. 


Mr. MeCririck’s mention of roller dies is interesting, and the author is aware that dies of 
this type are in use both on the Continent and in this country. The reduction in friction 
with corresponding reduction in power required will be appreciated. The suggestion that 
roller dies lessen the likelihood of unequal wall thickness is a good one, as this type of defect, 
if in existence at the commencement of the draw, is liable to be aggravated by the usual fixed 
and solid dies. It should be mentioned that these roller dies are arranged to rotate freely and 
are not power driven. 


ae 


With regard to drilling of billets prior to piercing, this operation is of course unnecessary 
where billets of standard or normal size are employed, as these involve no undue strain upon 
the piercing plant. In the ease of very large billets, however, it becomes almost a practical 
necessity to drill a centre axial hole in order that the frietion during piercing may not be 
excessive. This remark applies particularly to alloy steel billets. Mr. MeCririck deseribes a 
process of manufacturing thimble tubes in pairs very similar to that mentioned in the author’s 
reply to Mr. Walburn, with the exception of the sealing of the point. It seems surprising that 
electrie welding should be employed to seal that part of the tube which, after the cressing 
operation, is so well adapted for a final forging down. 


The author is grateful to Mr. MeKellar for his remarks coneerning the automatic process. 
His reasons for the popularity of this process are interesting, and it is probably the third 
which earries the most weight with the manufacturers. Certainly one does not expeet to see 
tubes as thin as 12 gauge coming from the Pilger mill, although this is by no means an 
infrequent size for the Dieseher mill. 


It is thought that Mr. MecKellar’s reason number one is a little severe. The waviness 
is pronounced on the surface of the pierced Pilger hollow, but negligible, and in some cases 
imperceptible in the finished tube. The internal bore of a Pilgered tube, when sighted, may 
have the appearance of being “rifled” like a gun barrel. But examination will show that the 
ridges which appear so pronounced in reflected light are hardly perceptible under a straight- 
edge. It is clear from Mr. MeKellar’s sketches and description that the Automatie Process 
has little in common with elementary plug rolling, in which the final outside diameter was 
determined by the particular roll groove employed at the final pass. 


The author has lately had an opportunity of witnessing in action the Automatie Process as 
deseribed by Mr. McKellar. It appears that this process is limited to a range of tubes between 
about 34 ins. and 4 ins. diameter. Generally two grooves are employed in the rolls, the second 
being slightly smaller than the first, and by this means the tube is rolled to about a sixteenth 
of an inch below the final required diameter. The plugs, although of special material, are liable 
to wear very quickly, and internal grooving towards the back end of the tube is not infrequent. 
For this reason the tube is next passed through the polishing mill, as mentioned by Mr. 
McKellar, where it is expanded to about ,!,in.—{in. oversize and any internal grooving 
diminished in the process. It will be remarked that this attention to the internal surface is 
peculiar to the Automatie Process, there being no occasion for such an operation with the 
other systems of tube manufacture mentioned in this paper. 


Final required dimensions are obtained in the sizing mill, in whieh, as in most reeling 
machines, no plug is employed. End cropping is performed cold after inspection, and the 
amount that is cut off is determined by the presence or extent of the internal grooving which 
may have persisted from the Automatie Mill. The question of taking the tensile test away 
from the end of the tube has been dealt with in the author’s reply to Mr. Gemmell. It is 
gathered that Mr. MeKellar’s suggestion must refer to the specific case of tubes with ends 
expanded cold, and subsequently annealed. In the majority of cases of swelling and swaging 
the operation is done with tube at red heat, and no subsequent annealing is required. 


M. Poinecet, who has had considerable experience of certain types of tube manufacture, 
will appreciate that billet wastage, tube cropping, sawing and tagging (in drawing operations) 
necessitate quite approximate figures, even in the purely illustrative examples on page 4. 

On the basis of D*L for billet and (D?-d?)L for hollows and tubes, the author assumed a 
mean mass figure of 225 for the latter against 245 for the billet, to allow for end cropping. The 
one exception was that of the hot drawn tube (process A), for which a figure of 200 was assumed 
to compensate for the additional cropping and tagging. As M. Poineet points out, the length of 
the cold drawn example should be 35 ft. 6 ins. instead of 45 ft. 6 ins. to give the designed mean 
figure mentioned above. 


12 


In reply to the subsequent questions arranged in alphabetical sequence :— 


(a) The maximum diameter of hollows employed in the elongator in this country is 
34 ins. It is understood that hollows of up to 4 ins. diameter are in use in America. 


(b) The same set of rolls is used for different sizes of hollow, and these are ‘apable 
of adjustment. There are, however, several sizes of guide dises, each of which eoyers a 
definite range of tube diameters. 


(c) The production of the finished tube from the pierced hollow is accomplished in 
one pass only, 


(d) Since the internal diameter of the tube is largely determined by the diameter of 
the mandrel, a range of mandrel sizes is employed. 


(e) To ensure an easy entrance of the hollow into the elongator, cireular inlet and 
outlet guides are provided. But the cent ‘alisine of the hollow is finally accomplished by 
the point of the mandrel, which precedes the hollow, and which automatically runs up 
the profile of the lower guide disc. 


(f) It should be pointed out that the speed of advance of the tube is a function not so 
much of roll speed, as of the relative angle of inclination of the rolls. A roll speed of 
800 feet per minute is typical of Ameriean practice, where outputs are high, and the roll 
or feed angles are generally more than six degrees, 


The peripheral speed adopted locally is about 500 feet per minute, and this speed, com- 
bined with a feed angle of six degrees, is designed to meet local requirements as regards output. 
It is not yet possible by the Diescher process to produce a length of tube even approaching the 
example of 40 feet given by M. Poineet, and the average maximum length of 17 feet or so is 
rolled in about as many seconds. 


The vertical Krupp type of extrusion press is in general use for non-ferrous metals, but 
would appear to have serious disadvantages when applied to the production of steel tubes. 
Manufacture by this process would be limited in its field of operation when tubes of laree 
diameter, thick walls and long lengths were required. The author is aware of two firms in the 
Midlands which attempted, some Years ago, to produce steel tubes in this manner, both of which 
reverted to more usual methods. Apart from the limitations mentioned above, it is considered 
that the necessary expenditure of power would be prohibitive. That this system has a com- 
mercial field in particular applications seems to be borne out by information received by the 
author, that alloy steel tubes of thin section are being extruded regularly and satisfactorily, 


ELONGATION PER CENT. 


Slraalless rae iddl afl elas 


= ULTIMATE TENSILE UP TO 28 ts/," 
STRIPS el erate ant Sa een Feri a 
Bg TEST LEN GT HS cut from hot rolled tubes 
a ---- TEST LENGTHS cut from cold drawn tubes 
| 
4o 5) 
REMARKS: Small sizes of tubes hiqher, 
3s large sizes of tubes lower figures of elongation. 
so 
25 


Is 
GAUGE _ LENGTH 


RATIO SQUARE ROOT OF SECTIONAL AREA 


ILLUSTRATING P. KERTSCHER’S CONTRIBUTION, 


fol 
andrel bar a 
fixed to rack : 


i 


Auxiliary, or 


Return Rotts 


Ptan - Top Poll removed Working Position - Showing 


relurn roll Opened off 
ILuustRATING D. McKELLAR’s CONTRIBUTION. 


THE MANUFACTURE, SURVEY AND TESTING 
OF ELECTRICAL EQUIPMENT. 


By G. O. WATSON. 


Reap 4rH Marcu, 1937. 


“A man is at all times entitled. or even called upon by occasion, to speak, and 
write, antl in all fit ways utter, what he has himself gone through, and known. and 
got the mastery of ; and in truth, at bottom, there iv nothing else that any man hasa 
right to write of. For the rest, one principle. I think, in whatever farther you write, 
may be enough to guide you; that of standing rigorously by the fact, however naked 
it look, Fact is eternal; all fiction is very transitory in comparison, All men are 
interested in any man if he will speak the facts of his life for them; his authentic 
experience. which corresponds. as face with face. to that of all other sons of 
Adam.”— Thomas Carlyle. 


The correct drafting of all forms of regulations, whether they be the Laws of Governance or the 
Rules of Lloyd’s Register, is a matter in which the attainment of perfection is as elusive as the quest 
for the ideal Surveyor. No matter what degree of care and patience is exercised in the choice of words 
or technical foresight, there arise in practice ambiguities or alternative interpretations other than those 
intended or even dreamt of. That the Rules for Electrical Equipment of Ships are no exception in this 
regard is evident to one engaged in the daily handling of plans and enquiries, and this must be the 
excuse for the form which this paper will take. 

The author has long felt that some guide in the application and interpretation of these Rules would 
be helpful, and for the somewhat elementary treatment of many points begs the forbearance of those 
having an electrical training. 

It is not possible within the compass of the present paper to deal with all the points one would wish, 
but it is hoped that members with points to discuss will not confine them to items mentioned in the 
paper, but will extend its scope to all matters relevant to the application of the Rules. 

It is proposed to deal seriatim with the various sections as they appear in the Rules. 


SEcTION 1—GENERAL. 

The submission of plans of electrical circuits, etc., was a requirement added to the Rules in 1933, 
and is regarded as the most important and beneficial addition of recent times. It is a practical 
impossibility for any Surveyor inspecting a vessel to determine whether all the cables are correctly 
proportioned and the circuits and switchgear correctly arranged, and this can only be determined from 
an examination of plans. Furthermore, colleagues at outports have not the time to devote to plans, and 
they can be handled more efficiently in a central office. This practice also keeps the London office in 
touch with the developments in all ports. Needless to say, plans should be submitted at the commencement 
and not when the installation is nearing completion, if expensive alterations, due to non-compliance with 
the requirements, are to be avoided. 

The plans required are :— 

(a) The switchboard elevation, showing the arrangement of apparatus and indicating 
materials used for the panels and insulating bushes. 

(6) A wiring diagram of the switchboard. 

(¢) The wiring of external circuits showing the sizes of main distribution cables, current 
loading, arrangement of sub-distribution boards, etc. It is important that the voltage and 
kilowatt capacity of the generators be specified. 


» 
“ 


[t is preferable, in the interests of efficiency, that all these plans be submitted simultaneously, 
double handling of each case being thereby avoided. In the majority of cases this is not done, and whilst 
it 1s desirable to submit cable sizes for approval as early as possible, it is felt that the non-submission of the 
remaining plans at the same time is not, in all cases, due to them not being available. Outports 
can assist in improving the efficiency of the plans section by asking shipbuilders to submit all these plans 
simultaneously. 


The necessity of submitting plans applies with equal force to additions or alterations made to an 
existing equipment, a fact which does not appear to be generally recognised. 


The significance of the deletion of the notation “ Elec.light” from the Register Book has not been 
fully appreciated, and erroneous ideas that an owner can, as it were, “contract out,” or, as he sometimes 
expresses it, “not class the electrical equipment” are still prevalent, an instance having occurred only 
recently. Even when used for lighting only, it may constitute a fire risk if not properly installed and 
maintained, and it is, therefore, part of the Underwriter’s risk. But if used for certain vital auxiliaries 
it becomes equally as essential as any part of the propelling machinery. If an electrical installation is 
fitted, it of necessity becomes an essential part of Olassification, 


Section 2—GeENERATING PLanr. 


The Rules now require that generators of 100 Kw. and over be inspected during manufacture and 
testing, and some general notes on points of construction and methods of testing are, therefore, of interest. 


Appendix 2 states the requirements to which the machines are to be designed and mannfactured, 
and applies to all sizes of machine. above and below 100 Kw. For the smaller machines, the 
manufacturer is required to carry out shop tests and submit certified copies of the results which, after 
checking and initialing, are to be attached to the first entry reports. 


InsPection.—Inspection during manufacture resolves itself into two categories, mechanical and 
electrical. The former can be further segregated, viz., the inspection of machined parts such as the fit 
of shafts, couplings, keys, bearings, the quality of materials and welding, and secondly, the assembly of 
composite parts, or sub-assemblies such as commutators, punchings or laminations, etc. 


The examination of machined parts is straightforward, but it must be borne in mind that the usual 
practice of electrical firms is to work to “limits” in accordance with “ fit” charts, and very rarely is a 
bore measured and the shaft machined to correspond. As a result, widely different degrees of fit or 
interference are obtained. This applies equally to couplings, armature hubs or spiders, bearings, 
commutator hubs, ete. 


Welding produced in electrical manufacturers’ works is generally satisfactory, but fabricated frames 
requiring heavy bending or rolling machines are frequently obtained from firms specialising in this class 
of work, and cases have been found, particularly where bare electrode welding has been resorted to, where 
such items as lifting eyes could be knocked off with a 7 lb. hammer. Generally speaking, the frames of 
D.C. machines are satisfactory, as the air gaps at the poles are comparatively large, but if A.C. machines 
with small air gaps have to be inspected, the design should be scrutinised to ensure that the frame is 
sufficiently rigid. The weight of punchings and windings tends to produce sagging and ovality, resulting 
in unsymmetrical air gaps. 

The shafts of most horizontal machines are usually much larger in diameter than torque 
considerations would dictate, as they haye to be sufficiently stiff to reduce the deflection. 


Cores built up of laminations present a difficulty, in that clearances have to be allowed in the bore 
in order that they may assemble readily, and yet a positive mechanical drive is essential. In the case of 
machines coupled to reciprocating engines, particularly Diesels, this point requires special attention to 
ensure that the core will not work loose in service. The core must be clamped tight endwise and the 
keys a good fit for the core drive. It is good practice to broach the core keyways after the core is built up. 


The commutator is another built Up or composite structure requiring consideration. It is good 
practice to “season” the commutator by subjecting it to heat stresses greater than it will experience in 
service. The best time to check the commutator is at the end of the heat run and it is well to observe 
the behaviour of the brushes as the machine is running and while it is decelerating to stop. An eccentric 
commutator can be detected by the movement of the brushes in the brush boxes and the presence of 


“high” or “low” commutator bars can be felt by a knock on the brushes. A high or low bar, as the 
terms indicate, consist of single bars raised or lowered in relation to the commutator surface and it is 
generally accepted that a bar high or low by 0-002 in, will eventually lead to commutator trouble and 
rapid brush wear. Eccentricity leads to brush wear due to the movement in the holder and may eventually 
lead to sparking troubles even if this does not show up at the time of test. 


Electrical faults in new machines are nearly always due to mechanical damage to the insulation or to 
insufficient creepage insulation. Under the first heading come roughness of surfaces against. which 
insulation is placed and chafing due to movement and rubbing. Connections should be supported and 
cleated to reduce movement and a watchful eye should be kept for potential trouble in service from these 
causes. Damage may also occur due to handling during erection and transhipping. But by far the 
greater precentage of failures will oecur due to insuflicient creepage. Failure rarely occurs by puncture 
of the insulation due to electrical stress. For instance 0-001 in. thickness of mica will stand up fo 
1000 volts whereas the normal mica thickness used on auxiliary generators is approximately 0-01 in. By 
creepage is meant the distance measured along the surface from one conductor to another or to earth. 
This surface may be an exposed one or may be an interior position. In the latter case, moisture may gain 
access and in the case of exposed surfaces breakdown may be brought about by deposits of dirt, carbon dust 
and moisture. In vessels having main or auxiliary Diesels an oily atmosphere will condense on the insula- 
tion which will then collect dust and dirt and under these conditions 220 volts may cause breakdown over 
considerable distances. These factors apply not only to machines but to all classes of electrical apparatus 
and the moral is—ample surface clearances and strict cleanliness. On machines of 100 Kw. the creepage 
distances rarely exceed ? in. at the minimum points but it is often possible to increase them by painting or 
enamelling the metal surface adjacent to the insulation. All insulation which is not naturally non- 
hygroscopic should be made so by impregnation. 


TESTING.—Generators of 100 Kw. and above, of the open type, must be capable of withstanding 
25 per cent overload in current at rated volts for two hours and 50 per cent overload for one minute. 
Some difficulty seems to arise in interpreting Appendix 2, clause 4 and an explanation appears to be 
necessary. For example “4 H.P. per 1,000 r.p.m. up to LO H.P. per 1,000 p.m.” might be written 
“O-4 ALP. per 100 rp.m.up to 10 A.P. per 100 p.m.” or alternatively *0°004 H.P. per r.p.m. up to 
0-01 per r.p.m.” To decide to which category a machine belongs :— 


H.P per 1,000 r _ Rated H.P. x 1,000 
een: MPs Rated r.p.m. 


The reason for adopting this method of discrimination is that the physical dimensions of regia 
vary inversely as the speed, e.g., a 60 H.P. 600 r.p.m. motor is larger and heavier than a 60 H.P. 950 r.p.m. 
machine but is similar in dimensions and weight to a 30 H.P. 300 1.p.m. motor. 


The tests which a Surveyor should witness and the order in which they should be carried out 
are as follows :— 
i) Heat Run or Temperature Test. 
(ii) Overload Tests. 
Gii) Regulation or Compounding Test. 
iv) Insulation or Megger Test. 
(v) High Voltage or Dielectric Test. 


G) Hear Ruy on Temperature Test.—Six hours is the usually accepted duration of the full 
load test on continuously rated machines and should generally be insisted on but in special cases may be 
curtailed at the Surveyor’s discretion if he considers, havi ing taken everything into account including the 
periodical temperature readings, that such a course is justified. On the other hand circumstances may 
arise which demand a longer period. The standard rule is that the test is to be continued until it is 
sufficiently evident that the temperature rise would not exceed the prescribed limits if the test were 
prolonged until a steady final temperature were reached. In this connection, however, it must be 
remembered that the temperatures will rise a further two or three degrees after the machine has heen 
stopped. 


4 


Thermometers must he attached to the stationary windings before the commencement of the run and 
readings should be recorded at intervals not less frequent than every half hour. In these circumstances 
it is unnecessary for Surveyors to be in attendance at the commencement of the test. provided they be 
present during the last hour to check the readings obtained and to compare them with those previously 
taken and see that a steady temperature has been attained. If full load has not been maintained by the 
manufacturer, irregularities will appear in the temperature curve and in all probability the temperatures 
will not be steady at the end of the six hours. A typical test sheet is given below and the temperature 
graph is shown in Fig. 1, An illustration of a machine with thermometers attached is shown in 
Fig. 2, though it should be noted temperatures on one, or at most two, shunt field Windings is generally 
sufficient. 


TypicaL Loc or TEMPERATURE TEST. 


TEMPERATURES DURING RUN IN °C. 


| SHUNT ‘ dj - AMBIENT 
FIELD. | SPEED AIR, 
TIME. |Vours| Amps. Shunt Field. Interpoles. | Series Field. FRAME. 
| r.p.m. | “ 
Amps. | Volts. | | No. 1. | No. 2. | No. 1.| No. 2.| No. 1. | No. 2. No. 1. | No. 2. | 
7 7 . ae 
6.80] 220 | 910 | 2-1 | 154 1,000 | Test ‘Commenced 
7.0 220 | 910 | 158 | 1,000 | 21 | 21 25 26 rs" 23 | «16 BA a5 it 
7.30} 220 | 910 2a 160 | 1,000) 26 rT | 30) | BIS 125 | dj v2) i ie Lith 
8:0 | 220] 910 | 24 161 | 1,000] 27-5 | 28 2. | BSH, ) 26 24) 23 baa Pa tek 9 
8.30] 220 | 910 | 2-1 162 | 1,000] 29 Pe | 9220) Bad: | OT 30 25 13 ear) | 
9.0 | 220 | 910 | 2-4 162 | 1,000} 29-5 | 30 33 SOCoe ee 31 26 | l4 14-5 | 
9.30] 220 | 910 ya 163 | 1,000! 30 | 30°5 | 385 POS ees) Sach 26°5 | 14°5 | 145 
| 
10.0° | 220 | 910 | 9-1° | “164 1,000 | 3075 | 31 34. | 365 | 28 | 32 27, | Leb i Tae | 
10.80] 220 | 910 | 21 | 164 | 1,000) 31 32 op 37 2S) SD! ca fa | 145 | 15 
11.0 | 220 | 910 | 2-1 164 | 1,000} 31°5 82 | 83h 37 28°5 | 32 28 14° | 14-5 | 
11.30) 220 | 910 | 2-1 | 164 | 1,000] 32 | 325 | 36 | 38 | 30 | 33 285 | 155 | 16°3 | 
12.0 | 220] 910} 2-1 164 | 1,000] 32°5 | 33°4 |. 36°3 | 38°5.| 30 33 29 15°5 | 16°5 
12.30 | 220 | 910 | 2+] | 164 | 1,000] 33 33°5 | 36°5 | BSD | 29 33°5 0) 14°5 | 16 
Final temperatures... 1% vanfe Goer] 96 40 10 31 34. 33 145 | 16 
fe " 3 Armature Core... 50 
idee? » Winding 50 
93 “ Commutator sae ASH, 4405 


The foregoing are actual readings taken during a test on a 200 kw. generator. The machine was stopped at 12,30 
to obtain final temperatures, and the slight increases over the last ‘ running” temperatures will be noted, 


The ambient temperature should be measured by several thermometers placed about level with the 
centre line of the machine and from 3 ft. to 6 ft. distant therefrom. Care must be taken that they record 
the temperature of the air entering the machine and are not affected by the heated air leaving the machine 
or by draughts. The value to be adopted for the ambient temperature for the determination of temperature 
rise is the mean of the readings taken at equal intervals of time during the last quarter of the test. 
Needless to say the machines should be shielded from draughts from open doorways, windows and the 
like, Similar amenities and sources of cool air are not usually found in engine rooms but rather the 
reyerse—a lack of sufficient cool air. 

The temperature of the windings is measured by thermometers placed on the hottest accessible 
surfaces of the stationary parts during the test period and by other thermometers placed on rotating parts 
immediately the machine is stopped. In all cases the bulb, except at the point of contact, is to be 
covered with a pad of felt, cotton wool or other non-conducting material } in. thick and at least 1} ins. 
square and pressed into contact with the surface to prevent loss of heat by radiation or convection. 
Alternatively a lump of putty or plasticine, placed over the bulb, may be used for this purpose. 


When measuring commutator temperatures a method sometimes employed is to wrap the bulb with 
lead foil leaving a projecting portion which is flattened and placed under a brush as soon as the machine 
comes to rest, 


As previously indicated, temperatures are to be taken during running and after stopping the 
machine. The highest temperature (not the mean) thus obtained is to be adopted to determine the 
temperature rise. Where the “back end,” ie., the end remote from the commutator, is accessible, it is a 
good plan to measure the armature temperature there, in addition to the “front end.” After shutting 
down the machine the temperatures should be observed until they reach their maximum and commence 
to fall. 


Gi) OVERLOAD Trsts.—Appendix 2, clause 4 contains requirements as to the overloads which 
machines are to be capable of carrying. No temperature limits are prescribed, and with machines for 
use on ships these overloads are unlikely to become limiting. A further consideration in the case of 
Diesel-driven generators is that, whereas the generator is capable of 25 per cent overload for two hours, 
the Diesel is only required to do ten per cent for one hour—and in many cases jibs at that. 

Shop practice varies in different works, but it is fairly common practice to carry out temperature 
tests by the Hopkinson method, especially in shops where the prime mover is not also made. It is an 
economical method, since it is only the losses which have to be supplied, and cost of supplying power is 
thereby reduced. Typical connections are in Fig. 8 and the excitation of the two machines is so 
adjusted that current circulates between the two armatures, one acting as generator and the other as 
motor. With the generating end adjusted to full load current, the motoring end will be carrying the 
same current plus the motoring load, and will usually be at 20 to 25 per cent overload. 


A word about brush angles might be said at this juncture. Brushes may be arranged so that they 
are radial, or may be sloped backwards in relation to the direction of rotation, known as “ trailing,” or 
tilted forwards, known as “reaction.” Brush gear designed for “trailing” will often be found 
unsatisfactory if run “reaction,” and vice-versa. This must therefore be taken into account when 
witnessing Hopkinson tests, as one of the machines will be running in the reverse direction to that for 
which it was designed, and the commutation may suffer accordingly. 


(iii) REGULATION OR CompouNDING TEStT.—Section 2, clause 2 (0) requires generators to be over- 
compounded 5 per cent under conditions of constant speed and excitation. The wording of this clause is 
somewhat ambiguous as it is not literally accurate, because with a 5 per cent change in voltage the 
excitation current will alter by a corresponding amount. What is intended is that after adjusting the 
excitation at no load, no further adjustment is to be made at full load. The conditions laid down are 
somewhat fictitious as no machine in practice runs at constant speed but they are expressed in that 
fashion as a basis for shop tests. 

In practice the speed of the engine ha& some bearing on this matter, the speed falling between no 
load and full load by an amount varying with different types of engine and depending on the governor 
characteristic. The rule as it stands may at some future date be modified to represent more closely the 
ideals aimed at. 


< in) 


The ultimate object is to maintain the busbar voltage as nearly constant as possible so that lamps 
are unaffected and motor speeds do not vary with the Joad on the generator. What is really important 
is that the voltage at no load and at full load when the generator is coupled to the engine shall be the 
same. It would also be ideal if the voltage remained constant at intermediate loads but this is 
unattainable as there is a small inherent rise in voltage at intermediate loads. 


The 5 per cent overcompounding at constant speed provided for in the Rules, compensates for the 
fall in the speed of the engine. Therefore, when generators are tested with their appropriate engine, 
the 5 per cent rule can be ignored and the compounding arranged to give equal volts at no load and full 
load. It is important when this test is made that the voltage regulator be untouched after having once 
adjusted the voltage at one or other of these loads. Judging by test results submitted for approval this 
does not appear to be universally appreciated. 

Having explained in detail the requirements of the Rules and the methods to be adopted, the tests 
which manufacturers should be requested to carry out will be described. 

(1) Furn Loap Temperature Test.—(a) If a Hopkinson test is made it should be 
continued for six hours with the generator end at full load. The motoring end will be at 
approximately 20 per cent overload. Temperatures of both machines are to be recorded and 
those of the generator are to be within the prescribed limits. So far as the motoring end is 
concerned the armature and series windings will be slightly in excess of the limits but the shunt 
field windings are to be within the limits. : 

After taking temperatures the machines are to be run up again with 25 per cent overload on 
the generator for one minute and the commutation of both machines is to be satisfactory. No 
further temperatures are required, 

(b) Where the machines are driven by an electric motor and loaded direct on to some form of 
resistance load, the full load run should be followed by one hour on 25 per cent overload, and 
commutation noted and temperatures recorded after both runs. 

(c) Where a combined test is carried out with the engine, after the ful! load run and 
temperatures have been taken, an overload test is to be made. If the prime mover is a Diesel, the 
overload should be 25 per cent overload in current at 88 per cent of normal voltage for one hour. 
This gives ten per cent overload in power, which corresponds to the standard requirement for 
Diesel engines. For steam turbines and reciprocating engines, the overload should be 25 per cent 
at normal volts for one hour. On these overload runs the commutation is to be satisfactory and 
temperatures are to be recorded. 

(2) CompounDING TEst.—(a) When tested at constant speed without the prime mover, 
compounding is to be as stated in the Rules, the field regulator remaining in the set position, ie., 
when full load is suddenly thrown off the voltage is to fall five per cent. 

(>) When tested with the prime niover, the voltages at no load and full load are to be equal, 
the field regulator remaining unaltered. 

(3) IysuLation oR Meccer Trsr.—This is to be taken between all windings and earth, 
and between the shunt and series windings, and is to be taken when the machines are hot, 

(4) Hien Vourace Dietecrric Trst.—This is to be applied to the same parts as the 
insulation test, and the requisite voltage is to be maintained for one minute. [t should be noted 
that for machines of 3 Kw. and above, the test voltage is 1,000 volts plus twice the rated voltage, 
with a minimum of 2,000 volts. Continental practice based on a minimum of 1,500 volts is not 
accepted. 

Emercency Trrp.—tThe reason for the rule, receutly added, requiring turbo-generators to have a 
switch fitted to the emergency governor to open the generator circuit breaker when this governor 
functions, is not universally appreciated. In the event of the overspeed governor coming into operation, 
the admission of steam to the turbine is immediately eut off and the set slows down until the generated 
voltage is below that of the busbars, and the machine becomes a motor drawing a reverse current from 
the line: but since the turbine is still under vacuum, the light running losses are small; the series 
winding also acts differentially, and the set can be motored up to a dangerous speed before the current, is 
of sufficient magnitude to operate the reversed current protection devices. Hence the need for making 
the emergency governor act direct on the circuit breaker, 


7 


SEcTION 8—SWITCHBOARDS. 

INSULATION.—Nemi-insulating materials such as marble and slate are required to have all conducting 
parts insulated with mica or other approved non-hygroscopic insulating material. The reason for this is 
that marble and slate are hygroscopic and when moisture is absorbed the insulation resistance is lowered. 
Slate suffers from the further disadvantage that even when obtained from the best-known quarries, metallic 
veins and salt inclusions are also found which cause low resistance. In the United Kingdom the best 
electrical slate is obtained from Aberllefeni. Belgian aud Spanish slates are of fair quality, relatively 
softer than Welsh slate and though freer from metallic veins, are more subject to the inclusion of salts. 

The uncertainty in the quality of slate and the high price of marble has led to the development of 
synthetic materials which in general are of two distinct types. 

(a) Compressed asbestos with a suitable binder or cement. 
(b) Synthetic resin with mechanical reinforcement. 

The characteristics of these are as follows :— 

(a) Asbestos wool forms the basis, consisting of short fibres which are mixed with a suitable binder 
such as slaked lime or portland cement, and in some cases a proportion of fine sand. This mixture is 
wetted, placed in flat moulds, compressed in an hydraulic press and subsequently left for a suitable period 
to become cured or aged. In this state it is are resisting i.e., will withstand an electric are on the surface, 
but it is a poor insulator and unsuitable for switchboards. After thoroughly drying it is, therefore, 
impregnated with materials, such as bitumen, in order to improve the insulating qualities and render it 
non-hygroscopic. In some processes the impregnating material is added in the original mixing. This 
material is supplied in varying thicknesses up to approximately 2 ins., and in the thicker materials it is 
frequently found that the impreguant has not fully penetrated to the centre. This is revealed by cutting 
a specimen and observing the lighter colour at the centre. In the course of manufacture the asbestos wool 
should be passed through a magnetic separator to extract any iron particles which may have got in whilst 
in the disintegrating machines, or from packing cases (nails, etc.). 

The mechanical strength is superior to slate and for this reason, and also on account of higher price per 
unit volume, it is usual to employ thinner panels. A synthetic panel two-thirds of the appropriate thickness 
for a slate panel is the usual ratio, and for panels not too heavily loaded or subject to shock, is satisfactory. 

Materials in this category are the British “Sindanyo,” ebony grade, and black “ Paxbestos,” and the 
American * Ebony Asbestos Wood.” 

(b) Synthetic Resin, better known under the trade name of ‘bakelite,” is used to produce a very 
high quality insulating board. In order to provide adequate mechanical strength it has to be reinforced. 
An absorbent paper, in itself a poor insulator, is impregnated with synthetic resin, built up in layers, and 
when subject to combined pressure and heat results in an insulation of high dielectric and mechanical 
strength. Cambric or butcher’s muslin treated in the same manner produces a similar material. The 
mechanical strength of such panels is evidenced by the fact that similar material is used for silent gear 
pinions and journal bearings. It can also be rolled in the form of tubes, and in this form is suitable for 
making sleeves for studs mounted in slate and marble panels or in steel panels. 

This type of insulation suffers from a characteristic known as “tracking.” Should a layer of dust 
and moisture accumulate on the surface between two adjacent parts of opposite polarity, the leakage 
current may carbonise the surface. The effect is cumulative and may result in complete failure. The 
remedy is to keep the surface clean and dry, or alternatively, to place a mica washer under the metal part 
in order to break the leakage path. 

Materials in this category are made in most countries under yarious proprietory names. 

The tests to which insulating materials intended for switchboard bases are subjected in order to merit 
approval are as follows :— 

(@) Bend Tresr.—The test piece Lin. x gin. x 9 ins. is secured within a clamp with the width in 
the horizontal plane so as to be supported as a cantilever. At a point 6 ins. from the nearest edge of the 
clamp a weight of 10 1b. is applied and maintained for two hours in an ambient of 15° C., and the material 
is to return to the original position when the weight is removed. 

The cantilever is then placed in an oven maintained at 90° C., and the weight again attached within 
1 minutes after placing in the oven, and after supporting the weight for two hours the permanent: set is 
to be not more than 10 mm. 


8 


(6) IxsuLaTion Resisrance.—Two holes 3 in. diameter, 14 ins. between centres, are to be drilled in 
a specimen of such size that the distance between either hole and the edge is not less than 1 in. A plain 
brass stud is then fitted tightly in each hole. 

The insulation resistance at a temperature of 90° C. in air, after the specimen has been maintained at 
this temperature for not less than half an hour and net more than one hour, is to be not less than 1,000 
megohms measured with a D.C. voltage of about 500 volts applied for one minute. 

At the conclusion of this test the same specimen is to be allowed to cool to between 15° C. and 25° C. 
in a controlled atmosphere of relative humidity 75 per cent. and the insulation resistance is to be not less 
than 1,000 megohms. j 

The test is to be repeated after the specimen has been immersed in sea water for 24 hours, being 
wiped dry immediately before the test is made. For this test the insulation resistance is to be not less 
than 50 megohms. 

(¢) Breakpown Test iy Ark.—With similar specimens an A.C. high voltage is to be applied 
commencing at about 3,000 volts and steadily increasing to 10,000 volts which is to be maintained for one 
minute without any sign of injury or any appreciable rise of temperature. 

After 24 hours immersion in sea water, a similar test with a maximum of 6,000 volts is to be applied. 

(7) Warer AxpsorBrion.—A specimen of the material 1} ins. square, having its four edges freshly 
cut is to be carefully weighed and then immersed in tap water at 15° C. to 25° C. for 24 hours. 

When weighed again after removal of surface moisture by wiping, the absorbtion is not to exceed 
1 per cent by weight. 

(¢) Corroston.—The material must not cause corrosion to metal in contact with it. 

(f) Non-INFLaMMaBiLiry.—The specimen used for the bending test is to be held for one minute in 
a bunsen flame and is to be self-extinguishing in not more than one minute after withdrawal therefrom. 

First entry forms require a statement to the effect that insulating materials are of an approved type, 
and following is a list of materials which so far have received the approval of the Committee. 


TABLE I. 
List oF APPROVED INSULATION MATERIALS FOR SWITCHBOARDS, 


7] 


NAME OF MATERIAL, MAKER. CountTRY. APPROVED 
Artlite ... ee ... Hirata Yakubutsn | Japan 1936 
Kenkyu-sho 
Asbestos ... ae «+ Comp. Gen. di Italy 1925 
(Black Faced) Elect 
Bakelite Bonded Paper .| Sankyo K.K, Japan 1934 
Tokio 
Biasbest ... nce .»» Monti Martini Italy 1928 
Black Paxbestos ... | Micanite and England 1935 
Insulators 
| Etronite ... on | Electro Isola Denmark 1936 
| Nipponlite a ...| Mitsubishi Denki Japan 1935 
Kaisha 
Pierrite ... aa i584 _ Italy 1928 
| Rikalite ... aa .-.| Fusi Denki Seiyo Japan 1934 
(Quality N) K.K. 
Sindanyo ... by. ..-| Turner Bros. England 1928 
’ Asbestos Co, 
Siluminite sce AE Siluminite England 1929 


Insulator Co. 


Tenacit ... we .-.| A.E.G. Berlin Germany 1926 
| 


FUSES BEHIND PanyeLs.—The placing of fuses behind panels is not permitted by the Rules, but a 
construction is gaining ground in Holland and Scandinavian countries which has received approval and 
deserves some comment, The distinction between “at the back of the board” and “behind the board” 
is perhaps rather subtle, but nevertheless there is a difference. The construction in effect might be 
described as a double-fronted board, and consists in mounting fuses on a framework behind the panel, so 
that they are fully exposed to view and not mixed up in the busbars and apparatus on the back of the 
panel. 


With modern cartridge and semi-enclosed fuses, in which the arc is constricted and not liable to 
injure surrounding objects, there is no great objection to this arrangement. At the time the Rule was 
drafted fuses were in an early state of development and open wire fuses were still in common use. Each 
case is considered on its merits, and the plans are scrutinised to see that the fuses are easily accessible 
without danger of the operator coming in contact with busbars and circuit breakers. It is invariably 
required that a minimum gangway of 600 mm., or approximately 2 ft., be maintained between the 
furthest projecting part and the bulkhead, and this must be kept free from obstructions which would 
hinder or endanger a man in getting access to, or replacing, fuses. There must be no obstructions which 
would cause a man to haye to worm his way through, or to stumble when approaching the fuses. This 
point also requires watching when making periodical surveys, and the reprehensible practice of using the 
space behind panels as a store or a cloakroom must be severely condemned. A typical approved arrange- 
ment is shown in Fig. 4. 


LockING oF CoNnNECTIONS.—Insufficient attention is paid to this important reqturement, and it is 
not sufficiently realised in shipyards and by the smaller electrical contractors that it is the most frequent 
cause of trouble. lhe vibration experienced in engine rooms leads to slack connections, with resultant 
overheating or broken circuits. In a heavy current circuit, a loose connection may easily lead to arcing 
and possibly fire or the destruction of a switchboard. 


Switches AND Fuses.—lIt is a common error on plans to find the fuses connected between the 
busbars, or supply, and the switches, so that they are still alive when the switch is in the “off” position. 
Fuses are liable to severe damage on a short-circuit, and also deterioration of contacts due to heat and 
other causes, and consequently provision has to be made for maintenance. The object of the 
arangement required by the Rules is to isolate the fuse from the supply wnen carrying out repairs or 
replacements. 


Reversep Current Trips.—No value is prescribed in the Rules for the value of reverse current 
at which the device is to operate. This should be from 10 to 15 per cent of the full load current of the 
generator which it is intended to protect, preferably the lower value. The method of testing is to 
parallel two generators and then reduce the excitation on the one which it is required to test. When 
the current in this generator reaches zero, record the current in the second generator. Continue to 
reduce excitation, thus causing this generator to take a reversed current, until the circuit: breaker opens, 
and observe the increase in current on the other generator at the time of opening. This increase in 
current as a percentage of the full load current of the generator determines the setting. The test should 
not be continued if the trips do not operate with 20 per cent reversed current. It is essential that the 
external load should remain steady during this test, so that the results are not vitiated by extraneous 
fluctuations. This test should be carried out on all new vessels and at the time of periodical surveys, 
taking each generator in rotation. 


Kartu TEstinG.—The most common method of earth testing provided on switchboards consists of 
two lamps connected in series with the mid-point earthed. his is a very crude form of indication 
and although it complies with the requirements it is only of service for indicating very approximately 
the condition of the insulation. It has the disadvantage that it only indicates the difference between the 
leakage on the two and in general only serves to indicate dead earths. Leakage may be excessive on 
both poles but, provided it is approximately equal, the lamps will not indicate the presence of minor 
faults. The principle on which it operates is that an earth on one pole bye-passes or, if it is a dead 
earth, short-cireuits one of the lamps causing that one to either dim or go out altogether. The lamp on 
the other pole burns brighter and the difference in illumination given hy the two lamps is the indication 
that all is not well. 


10 


A variation of this method consists of a single lamp with a two-way switch or two lamps with either 
plugs and sockets or single-pole switches, the arrangement in either case being to connect one lamp from 
one pole to earth. If the earth current is sufficient it will cause the lamp to glow. The weakness of 
this method is that the earth leakage current must be excessive before any indication is obtained, as will 
be seen from the following table which gives the minimum current and volts necessary to produce a 
glow on the filament which is visible in daylight with a black background. 


TABLE II. 
Maximum 
ae z Insulation 
Type of Lamp. Watts. | Volts. Me sare tae dae Resistance of 
| 1 ioe 8 “| circuit to cause 
visible glow, 
| 

Volts. Amps. Ohms. 
Vacuum... Fe ee nae 40 110 12 099 990 
Gas Filled ... a wae ae 40 110 14 152 632 
Vacuum ... ae rag 3 60 110 10 “197, 785 
Gas Filled ... ve a ee 60 110. | 13°5 +220 438 
Carbon ae “EF, vie +8 16 110 30°5 "128 621 
Vacuum ... i at Aan 40 220 21 05! 3770 
Gas Filled .. SAF oi miss 40 220 32 ‘097 1940 
Vacuum... es Uae om 60 220) 195 | 065 3080 
Gas Filled... See oe. eA 60 22() 30 aig: | 1630 
Carbon... Hed a a 16 220 73 “072 2040 


By way of comparison, it should be noted the minimum insulation resistance permitted on 
Periodical Survey is 100,000 ohms, which allows a leakage current of -0011 on 110 volts and -0022 on 
220 volts. With a number of circuits in parallel, each with an insulation resistance of the minimum 
value of 100,000 ohms, the leakage will, of course, be greater, but there is still a vast gap between the 
permissible leakage and the values indicated above. 


An alternative method of earth testing consists of two voltmeters (which can be miniature 
instruments in order to keep down cost and space occupied), connected in series and having the midpoint 
earthed as in the lamp method. This is subject to similar criticisms, but is slightly more sensitive in 
that variations in the voltmeter indications are more easily seen than variations in lamp illumination. 


A better method is the use of a meter (in effect a voltmeter) calibrated in megohms having one 
terminal connected to earth and the other to a two-way switch by means of which it can be connected to 
either pole. This gives a direct indication of the state of the insulation. Still another method consists 
of a neon lamp connected to a potentiometer resistance. The lamp glows with a very small leakage 
current comparable with what may be considered the borderline between safe and unsafe values. 


Fusipte Cur-ours.—The significant purpose of the word “approved” in clause 6 (¢) appears to 
have escaped general notice if the number of fuses which have been submitted for approval is any guide. 


| 


11 


Since everything affecting classification is necessarily subject to the Surveyor’s inspection and satisfactory 
report the use of this word in any rule involyes a subtle distinction and implies submission of details to 
London for approval. 


The position is that to-day literally scores of firms, large and small, are engaged in the manufacture 
of fuses and the design and workmanship in many instances leaves much to be desired. ‘The contacts are 
in many cases flimsy and weak and the are rupturing capacity on short cireuit is doubtful. The Rules 
contain requirements as to temperature rise and general construction. With regard to the former it is 
impracticable to carry out tests after installation and the only satisfactory method of deciding whether 
the design is satisfactory is by means of properly conducted laboratory tests which can be approved once 
and for all. 


Following are the British Standard tests which all fuses should satisfy in order to merit approval. 


(1) The insulation resistance should be not less than 100 megohms measured between :— 
(a) the fixed contacts (with the fuse carrier in position and the fuse wire or link removed). 
e 
(b) the fixed terminals and the case, if any (with the fuse carrier in position). 


(2) The cut-out should be mounted vertically in still air and tested, starting from room temperature, 
for compliance with the following requirement: — 


The fuse link is to blow on a current equal to 1°9 times the rated carrying capacity in less than 
30 minutes. The cut-out is then to be allowed to cool to approximately ambient temperature. It is then 
to be rewired and is to withstand a current equal to 1°6 times the rated current for at least 30 minutes. 


(3) In order to test the breaking capacity the cut-out must repeatedly and satisfactorily without 
damage to itself, clear a circuit adjusted for the appropriate short-circuit current given in the following 
table when wired with a fuse link in accordance with the rated capacity. 


TABLE III. 
| . 
Rated Carrying Shona rama 
Current. Current. 
Amperes. Amperes. 
ij 500 
Ld 1,500 
30 2,000 
60 4,000 
100 6,500 


When the cut-out is intended for use in a metal case it should be tested in the case with the latter 
connected to the negative pole of the test battery or generator through.a resistance not exceeding 
05 ohms. The source of supply should be preferably a secondary battery rated at not less than 
500 ampere hours on a one hour rate of discharge ard capable of giving the short-circuit current 
required. The open-circuit voltage of the battery should be 260 volts. Cut-outs should operate 
successfully six times in succession without the renewal of any part other than the fuse link and 
the asbestos tube. 


12 


The cut-out shall he deemed unsatisfactory should any of the following phenomena occur :— 
(i) Holding of the main are for any appreciable length of time. 
(ii) Any visible sign of arcing to the case, if of metal. 
(iii) Ignition of the cut-out or attached apparatus. 
(iv) Mechanical damage to the fuse carrier, fuse contacts, base, fixed contacts or metallic 
case, sufficient to render one or more of them unserviceable without repairs being effected. 

(4) To test for temperature rise, the cut-out is to be tested vertically in still air in the containing 
case (if any) in which it will be installed in service. ‘The cut-out is to be wired for its maximum rated 
current, with a fuse link identical with that which will be employed in service. The maximum 
temperature rises of the top fuse contacts, fixed contacts and fixed terminals, are to be measured by 
copper-constantan thermo-couples attached by means of a low melting point alloy. The points of 
attachment are to be those at which the maximum temperature rises are expected to occur. After the 
cut-out has carried its maximum rated current continuously for four hours, the maximum temperature 
rises of the contacts and the fixed terminals are not to exceed 60° C, and 28° C. respectively. 

Following is a list of approved fuses. Attention at this stage might be called to the requirements 
for tankers classed for carrying petroleum in bulk, viz., that fuses are to be of an approved filled 
cartridge type. The only fuses of this type approved up to the time of going to press are the Siemens 
“Zed” pattern, and Parmiter Hope and Sueden’s “ Aeroflex” pattern. 


TABLE IV. 
APPROVED FUSES. 


TRADE | wo f CAPACITIES Pe ay DATE 
NAME, es APPROVED. REFERENCES. | APPROVED, 
Zed... ...| English Electric All sizes up to High rupturing 1936 
Co., and Siemens 400 amperes. | capacity, standard 
Electric Lamps | type for ordinary 
and Supplies Ld. duty, 250 and 500 
| volts. 
| | 
ARTIC... ...| Artic Fuse & | 15, 15/25, 30, 60 | = | 1935 
Mfg., Co., Ld. and 100 amperes. 
SLYDLOCK ...| E. Wilcox & Co... 5 amperes, No, 534 1936 
| Ld. 15 - » 1533 
20° 5, » 1582 
30 ¥ » 30384 
SIMPLEX...) Simplex Electric 15 amperes. | — 1936 
| Co., Ld. 
TRIUMPH Castle Fuse & | All sizes up to — 1936 
Eng., Co., Lid. ' 100 amperes. 
| | 
| 
AEROFLEX ...) Parmiter Hope | 15 amperes. | Type AFB 1936 
| and Sugden Td. 30 3 » AFM 
CO tele, » AFS 
60 x » LDF-O 
Desco ......, G. P. Dennis Ld. | All sizes up to | — 1934 
100 amperes. 


Examination of fusible cut-outs on the occasion of periodical surveys is an important function which 
should never be neglected. Nothing is more calculated to cause fires due to electricity than the 
overfusing of circuits. No engineer would dream of making his boiler safety valves inoperative by 
fitting heavier springs or screwing them up solid, and yet how often will the self-same engineer render 
his electrical safety valve—the fuse—inoperative by doubling and trebling the fusible link. 


In many of the older vessels there was perhaps some excuse, because there was no indication as to 
what the correct size of fuse should be. This no longer holds, as it is a requirement that all fuses be 
labelled with the size of the cable they protect, and the size of fuse wire to be used. It is important to 
see that this requirement is carried out. It applies to every fuse in every new vessel. 


In some cases it is found the asbestos tube, which is a feature of most porcelain handle rewirable 
fuses, is not renewed. This is a vital part of the fuse, particularly in the case of those fuses on the main 
engine room switchboards, where the generators are of large capacity. They are essential adjuncts for 
the rupturing of heavy short cireuits, and on periodical survey their presence should be confirmed. 


Section 4.—Conpuctors. 

'TINNING OF ConDUCTORS.—It is required that where the insulating covering of the conductor contains 
sulphur—i.e., V.1.R. cables, each wire is to be efficiently and uniformly coated with tin free from all 
impurities. A tinning test is not yet included in the Rules but since some such test may be required in 
order to determine in a specific instance whether the tinning is efficient, details of appropriate tests are 
given hereunder. As a general rule it is only necessary to test for pinholes and similar blemishes and 
the appropriate test for this is the so-called polysulphide test. The second test, which is not so frequently 
applied, is to determine whether the thickness of the tinning is sufficient and is known as the persulphate 
or Shurmann-Blumenthal test. 


The polysulphide test consists in taking samples of the tinned wire from the stranded conductor, 
either before or after vulcanization, coiling them into a helix with a diameter between 24 and 30 times 
the diameter of the wire. After de-greasing and carefully cleaning, each sample is then immersed in test 
solutions, each operation being performed six times, the operations being as follows :— 


(1) Immersion for one minute in hydrochloric acid as defined below. Wash in clean water 
and wide dry. 

(2) Immersion for 30 seconds in sodium polysulphide solution as defined below. Wash in 
clean water and wipe dry. 


Kach sample is then examined under a lens to ascertain if copper exposed through openings in the 
tin coating has been blackened by the action of the sodium polysulphide; if so the sample shall be 
considered as having failed. 


The hydrochloric acid is to have a specific gravity at 60° F. (15°6° C.) of L088. 


The sodium-polysulphide solution is to have a specific gravity of 1142 and is to be made by dissolving 
about 25 grammes of pure sodium-sulphide crystals in distilled water made up to 100 ¢.c. then adding 
powdered sulphur in excess of the quantity required to saturate the solution (about 25 gr. per 100 e.c.) 
and boiling for about one hour, Cool and filter the solution and dilute with distilled water to the specific 
gravity specified. 


The persulphate test need not be described in detail, but it depends on the fact that copper, in the 
presence of ammonia and an oxidising agent, develops a very deep blue solution. A sample of tinned 
conductor, having an exposed surface area of 20 sq. cm., is de-greased, the ends are sealed with paraffin wax 
to protect the exposed copper end, and the sample is immersed in the solution for ten minutes. If at any 
points the tinning is faulty, copper is dissolved from the wire and the solution is coloured blue, the depth 
of the colour depending on the amount of copper dissolved. By transferring the solution to a tall 
Nessler tube and comparing with a second tube containing a known standard amount of copper, it can 
thus be determined whether the sample is above or below the standard requirement. Quantitative 
results can be obtained if required, by exactly matching the two tubes. 


14 


Vortack Dror.—The Rules permit a pressure drop of 2 volts plus 3 per cent for lighting and 
2 volts plus 5 per cent for power and heating. This is obviously only suitable for circuits of 110 volts 
and above, and low voltage circuits such as 12 volts, frequently used on yachts and small craft were not 
contemplated. This Rule will, therefore, require revision to meet such cases, 

PROPORTIONING OF ConpuCTORS.—The size of conductors is to be so selected that the rated capacity 
of the cables is not to be exceeded when they are carrying the maximum load probable under the heaviest 
conditions of service. In other words a diversity factor may be applied, i.e., it may be assumed that all 
the devices connected to a distribution board will not be in operation simultaneously. This is a factor 
which gives much food for thought when dealing with plans as no hard and fast rule can be laid down. 
In the case of engine room auxiliaries great caution requires to be exercised, as obviously no risk must 
be taken, but where standby or duplicate pumps, etc., are connected to the same board, it simplifies 
matters if it is known that they are not intended to run simultaneously. Some shipbuilders include on 
their plans a schedule for each distribution board indicating the total connected load and the probable 
load and it would be most helpful if this practice were extended. In some cases the load can be 
sub-divided into sea load, manceuvring load, and harbour load. 


In the case of final sub-circuits obviously no diversity factor can be permitted. Galleys also require 
discretion as the loading is in the hands of non-technical people who are liable to switch everything on, 
regardless of consequences. Where a diversity factor is apphed it is important that adequate overload 
protection be provided and this should be preferably a circuit breaker which can be set much closer to 
the rated capacity of the cable than a fuse. 

The proportioning of cables supplying groups of winches is subject to widely varying practice in the 
different shipyards. This, however, is too wide a subject to discuss at this juncture and is at present 
under investigation. 


STANDARD SIzES.—With reference to the tables of recognised standards, the question of continental 
sizes in metric units is under consideration. Continental Standards do not line up with the British 
Standards but fall intermediately between the various sizes, Consequently a separate set of tables would 
be appropriate. 


SEction 5.—INsuLaTIon aND PRorective COVERING oF CABLES. 

Vutcanisep Rupper INsuLaTeD CaBLEs.—The Rules require a layer of pure rubber next the 
conductor, followed by two layers of vulcanising rubber. Alternatively, the pure rubber may be 
omitted and the layers wholly vulcanised, provided the quality of the tinning is such that there is no 
corrosion of the tinning in the finished cable. 


The pure rubber requirement is a relic of less enlightened days, and its use is now to be discouraged. 
In fact, it may in due course cease to be recognised. The change of thought and practice in regard to 
this is interesting. Pure rubber was originally intended to prevent free sulphur in the vulcanised 
rubber from attacking the copper. At that time considerably more sulphur, amounting to seven or 
eight per cent of the mixture, was used for vulcanisation, and in the final product there remained about 
two per cent of free sulphur. This attacked the copper; hence the layer of pure rubber to act as a 
barrier and incidentally to increase the insulation resistance. It was later found that the sulphur 
migrates through the pure rubber and eventually attacks the conductor. 

Now if, as so frequently happens, moisture gains access by travelling up the stranded conductor, 
sulphuric acid is formed and the tinning is dissolved away. Interaction then takes place between the 
copper and the rubber which, under favourable conditions such as in hot situations and in the tropics, 
results in the rubber becoming soft and tacky. 


Nowadays much less sulphur is used for yulcanisation. amounting as a rule to only two per cent of 
the mixture, and the amount of free sulphur after vulecanisation is practically nil, so that the layer of 
pure rubber is no longer essential and can be omitted. In any case, it does not fulfil the purpose for 
Which primarily it was used. 

The manufacture of vulcanised rubber is an interesting process, and a few words on this vital 
material may be of value. The Rules contain only two tests—a high voltage test and an insulation 
resistance test, but these tests unfortunately give no guarantee that cables which pass them will be 


15 


lasting and durable in service. One is therefore perfectly entitled to ask why further tests are not 
instituted. The matter is not simple of solution, since rubber being an organic substance, and methods 
of manufacture varying between different manufacturers, it is extremely difficult to find a single set of 
tests which would be appropriate to all. 


Rubber oxidises with age, particularly when stressed mechanically, such as by bending the cable, and 
also when subject to temperatures in excess of about 130°F, The object then is to produce a rubber 
which will resist ageing or oxidising during the life of the cable—say 25 to 30 years. 


The aim of any artificial ageing tests must be to produce in a few hours or days an amount of 
ageing equivalent to four or five years and various recognised tests will be described later but it is first 
necessary to observe that whereas a given test will in the case of some rubber mixtures give a true 
indication of the probable life, in other isolated cases it would give a false indication. Furthermore 
some mixtures which would fail a given test might be perfectly good specimens. The tests referred to 
in these comments are the Geer Oyen test, the Oxygen Bomb test and the Air Bomb test. 


There are also other tests of a mechanical nature such as tensile tests and stretching tests to 
determine whether the mechanical properties are good and the vuleanising is complete. Rubber is an 
accommodating substance in that rubber technicians can produce at will vuleanised rubber of an infinite 
variety of qualities, varying from extremely soft rubber to the hard vuleanite used for pipe stems, etc., 
and with a variety of other properties but usually the attainment of one quality means the sacrifice of 
another. We must, therefore, be careful to ensure that by specifying certain tests we do not bias the 
manufacturer towards producing something which just meets those requirements but sacrifices some 
other essential quality in order to do so, 


An essential adjunct to every cable works is a well-equipped laboratory in which a daily examination 
of the products is made. No faith can be placed in any cable works which does not carry out a constant 
daily examination and control of the ingredients in the mix. Owing to variations in the quality of the 
pure rubber as received from the plantation it is necessary to make slight variations in the mixture. It 
is also necessary for the manufacturers to examine the ingredients to ensure they are in accordance with 
specification. In the better class works no mixture is ever allowed to go into production until the 
chemists have taken samples, vulcanised them and carried out tests but on the other hand one comes 
across isolated cases where adequate control is lacking. 


The usual manner in which rubber fails by ageing is by hardening and losing its physical properties. 
Elasticity disappears and the rubber is said to have “perished” and this is due almost entirely to 
oxidation. 


To test the characteristics of rubber a series of tests are made. First the tensile strength is 
obtained by stretching samples of the usual test piece shape. Elongation expressed as a percentage runs 
into hundreds and may be as high as 1,000 per cent with certain types of rubber but for dielectric 
rubber seldom exceeds 600 per cent. 


Secondly a stretch or “set” test is made. In this test the specimen is marked with two lines, say 
1 or 2 inches apart, fixed in a pair of grips and stretched to say three times this distance for a stated 
time of the order of 12 to 24 hours after which it is released. Ata specified time after releasing the 
tension the marks are again measured and the permanent set determined. This test is obviously 
arbitrary in character and the times and amount of stretch can be arrived at arbitrarily but having done 
so it allows different samples to be compared in a quantitive manner. It shows the difference between 
samples which are elastic and others which are more or less “ dead.” A rough test of this sort can also 
be made on any piece of rubber taken from a cable and stretched by hand, and noting how it recovers. 
A good sample should easily stretch to at least twice its original length. 


To remove the rubber from the conductor without slitting it, take the sample between thumb and 
fingers, and twist it until the conductor can be withdrawn. If this fails, stand the sample in mereury 
for a few hours. 

Finally, we come to the accelerated ageing tests, the object of which is to reproduce in a matter of 
hours an amount of ageing equivalent to so many years. ‘The ageing produced must be not only one of 
degree, but of the same type physically and chemically. 


16 


The best-known and most commonly used test is the Geer oven test. Samples of rubber dielectric, 
after removing the outer coverings and the conductor, are placed in an oven at an elevated temperature 
usually about 180° F. (82°C.), in a constant stream of air for two or three days. At the end of this 
period stretch tests are taken and compared with the original test results. In practice, one week in the 
oven is roughly equivalent to two years natural ageing. 


Another ageing test is the Bierer-Davis Oxygen Bomb test introduced in 1925, which is more severe 
than the Geer Test. The samples are placed in a strong steel autoclave in an atmosphere of oxygen, and 
subjected to a pressure of approximately 300 Ibs. per square inch at a temperature of 70°C, Comparison 
of physical properties is again the basis. Twelve hours in this bomb produces, in certain cases, ageing 
equivalent to approximately twelve months natural ageing in the tropics. 


A variation of this test is the Air Bomb test, which uses air instead of pure oxygen, and works with 
approximately 80 Ibs. pressure at a temperature of 260° F. (127°C.). It is the most severe test of all, 
and ordinary stocks cannot survive more than a few hours of treatment. It is useful because results 
can be ascertained in a few hours instead of having to wait days or weeks, 


It will be deduced that oxidization is practically the sole cause of deterioration in rubber cables, and 
it follows that to prolong life oxygen must be excluded, whether it be from air or water. Ozone is 
particularly harmful. 


A test which illustrates this very well consisted of taking lengths of cable, some lead-covered and 
some not, and subjecting them to 180° F. for a period of twelve months, periodical tests being made. 
The results showed that in thirty days the unprotected sample had deteriorated to an excessive degree, 
whereas the lead-covered sample was unchanged after twelve months. 


It is found in practice that numerically the largest number of faults occur within three feet of the 


ends of the cables, and these can be practically eliminated if the ends be sealed. Sealing is a very simple 
process and can be carried out in several ways. 


(a) By providing a sealing chamber at the cable entry, if a box is used. 

(6) By the use of plastic compounds similar in appearance to plasticine or putty, but much 
softer and non-hardening, i.e., it remains permanently plastic. It is simply pressed round the 
end of the insulation to seal the interstices round the conductor. 

(c) By dipping the end of the cable in a suitable compound. 


Another factor which helps in this respect is the question of the rubber adhering to the conductor. 
Obviously, cables would not require sealing if the rubber adheres closely to the conductors, and in some 
countries this is the practice. The objection is the difficulty of stripping back to make connections, and 
also in subsequently cleaning the conductor, 

The question of temperature is also important. The current ratings of cables are based on a 
temperature rise of 20° F., and an ambient of 100° F., giving a final temperature of 120°F. This figure 
will give a reasonably long life, but 130° F. for short periods is not injurious. It will be seen, however, 
that for very hot situations as, for instance, screen bulkheads in boiler rooms, rubber is unsuitable, and 
such situations must be avoided or another type of cable selected. Cables on deck where they may be 
exposed to tropical sun, are another instance where rubber must be regarded as unsuitable. Undoubtedly, 
lead covering is a considerable help in combating these unfavourable conditions, and sealing the ends js 
another aid. 


When used in ambient temperatures above 100 F., the current should be reduced in the following 
ratios :— 
Ambient air temperature... 105° F, oy 110° F. + 115° F. 
Reduction factor —.., 2¢ O86 ih 0°68 ay O45 
BuNcHING OF CaBLEs.—Another consideration which affects heating in cables is that of bunching. 
This is a factor which is extremely difficult to legislate for when approving plans, as it is impossible to 
know exactly how the cables are to be grouped, 
It will be noted that the tables of current ratings are for single cables. It is obvious that when 
cables are bunched, some of the cables will be excluded from contact with the air or other cooling medium, 


y 
17 


and radiation will be restricted. The effect of this is that for four single cables in a bunch, or enclosed 
in one conduit, the current capacity is reduced by 20 per cent. The ratio of carrying capacity for 
various degrees of bunching or enclosing in one conduit, is as follows :— 


Not more than | Not more than Not more than Not zpOrS then 
2 single-core 4 single or 6 single-core | 10 single-core 
me Saisie 2 twin cables. | 0" 3 twin-core | or 5 twin-core 

hte - en hee cables. , | cables. 
| 100% 80% 70% 60% 


It may be argued that all the cables in a bunch will not be carrying their full capacity simultaneously, 
This, of course, has some bearing on the matter but again is difficult to legislate for. Nevertheless, if 
the cables in the centre of the bunch are carrying their full rated current they will undoubtedly become 
hotter than is good for them and bunching must, therefore, be avoided. The author has seen some 
particularly bad examples of bunching, consisting of banks of cable ten inches square containing over a 100 
cables. There is no doubt whatever that this is extremely bad practice and should not be permitted. Apart 
from the extra heating question what worse example could there be of putting all the eggs in one basket ? 

(a) Failure of one cable will mean disturbing scores of others to effect repairs. 
(4) Failure of one cable may very well destroy all the others. 

H.R. CaBLes.—Before passing on to paper and varnished-cambrie cables a word must be said about 

“H.R.” cables. 


The origin of the term “H.R.” is somewhat obscure and there are different versions but whatever 
it may be it certainly does not signify “ hard rubber.” The latter is “ vulcanite,” the substance that pipe 
stems, etc., are made of. 

H.R. cables first came to the fore about 1928 and consist of a dielectric of ordinary vulcanised 
rubber encased in a special composition designed to be oil and water resisting. The outer casing replaces 
the lead sheath and subject to satisfactory tests, usually carried out at the National Physical Laboratory 
this cable is accepted in lieu of lead covered cable in engine rooms and similar situations. 

Lead sheathing performs two main functions when used on V.I.R. cables. 

(a) To protect the rubber dielectric from oxidization and the effects of oil. 
(6) To form a continuous sheath of earthed metal. 


It is in connection with the former property that H.R. sheathing as a substitute for lead comes to the 
fore. Lead unfortunately cracks when subject to severe vibration and then ceases to fulfill its functions 
in the protection of the rubber. It has previously been explained that rubber compositions can he 
designed to meet various conditions and in this instance resistance to oil and sea water are the prime 
objects. In most cases the insulation properties are inferior so that insulation rubber has still to be used 
as a dielectric under the H.R. though at least one manufacturer manages to dispense with this with 
satisfactory results. 


Each manufacturer has his own formula and it is necessary, therefore, before approval can be given 
to submit samples for test. The stringency of these tests will be seen from the following :— 

1. SampLes.—The test required at the National Physical Laboratory necessitates samples of cable, 
two of small size such as 7/029, and two larger such as 19/052. About 20 yards of each is sufficient for 
these tests. 


2. OVEN Trst.—One sample of each type and size is clipped to a perforated metal tray in accordance 
with usual ship practice and one batch subjected to Diesel oil spray and a duplicate batch to sea water 
spray followed by Diesel oil spray. 

The samples for this test are mounted in ovens maintained at 150° F. for ten weeks, except that 
each working day the oven is switched off for a few hours and allowed to cool. Each day one oven is 
charged with Diesel oil spray for one hour and the other chamber with sea water spray for one hour and 
Diesel oil spray for one hour. ‘A potential of 240 volts D.C. is maintained on the conductors throughout 
the ten weeks, except for occasional short periods when the dielectric test is applied. 


18 


x 


Periodically the insulation resistance at 60° F. and 150° F. is measured and a dielectric test. of 
2,000 volts A.C. applied for one minute at 60° F. During the last two weeks, a periodic test of 
1,000 volts A.C, for 15 minutes at 60° F. is made. Certain additional tests on the mechanical properties 
of the dielectric are also taken. 

In addition to the foregoing, the following tests are required and may be made at the makers’ 
works in the presence of a Surveyor. 


3. Impact Test.—A length of cable of each size is cleated in turn to a metal support. A wedge 
shaped hammer head of mild steel, having its thin edge rounded off to about 4 inch radius, is arranged in 
guides so that the thin edge falls across the cable. The hammer head is repeatedly dropped on to the 
cable until break down of the cable occurs, 2,000 volts A.C. being applied after every five blows. The 
weight of the hammer head is one pound dropped 12 inches for the small cable and two pounds dropped 
18 inches for the large. 


4. IaNrrapiiiry.—Samples are tested by holding them horizontally in a Bunsen flame for one 
minute, withdrawing and noting the time required for the flame to extinguish, which should not exceed 
approximately one minute. For this purpose the flame should be adjusted to approximately 3 inches 
and the sample fixed 2 inches from the orifice of the burner. ‘The samples are to be shielded from draughts. 
This test is to be witnessed by a Surveyor. 

5. Dieuectric Trest.—A sample of not less than 20 feet of each size to be tested at 1,000 volts for 
15 minutes after 24 hours immersion in water. This test is followed by a breakdown test. 

6. Benpinc Test.—A bending test is carried out in accordance with B.S.S. 608, clause 19. 

Table V. is a list of cables which have been approved for use in lieu of lead covered cables in engine 


rooms, etc., where specified in the Rules. It should be pointed out, however, that this approval does not 
extend to tankers carrying petroleum in bulk where lead sheathing is required for a different purpose. 


TABLE V. 
Type “HR” cables having a sheathing of special compound accepted in lieu of lead sheathing 
for use in engine rooms, etc. 


SUPPLIER. 58 ees Y bs A aoe 

British Insulated Cables, Ld. POF Bre ifs eat pa HR 1928 
Edison Swan Cables, Ld. ee Fé ee 3% oe ee Virite 1930 
Callenders Cable & Construction Co., ial oa A fy Ae: HR 1931 | 
W. T. Henley’s Telegraph Works Co., Ld. ... sre B Te HR 1931 
The Macintosh Cable Co., Ld. oe <e ta ee ee Maconite 1932 
The General Electric Co., Ld. and Pirelli General Cable Works, Ld. HR 1933 
Johnson & Phillips, Ld. se we S5. eee A Bae HR 1935 
The Craigpark Electric Cables Co., Ld. mr +e ae f Brumite 1935 
The Liverpool Electric Cable Co., Ld. oe — Fe ia Lecite 1935 

| Derby Cables, Ld... aes 7 ch ri ae Ae Derite 1935 
Siemens Bros. & Co., Ld. ... Sat ae ne << one HR 1935 


19 


Leap SHEATHING.—Reference has been made to the cracking of lead sheaths due to vibration, and 
it should be pointed out pure lead is unsuitable where there is much vibration. Purchasers sometimes 
specify pure lead, thinking thereby they are getting a better article, which is far from being the case. 
Certain alloys have been found, as a result of extensive research, to be superior, as will be seen from the 
following table. 


TABLE VI. 
Compositions or LEAD ALLOY SHEATHINGS. 
! ies a ae a Bs 
y >OSTT y Pare, ‘ > Tato 
CoMPosITION (Percentages by Weight). Se INES 
ALLOY. | Lim1T,* 
| | . 
Tin. Antimony. | Cadmium. Lead. Ea sati Gat 
— Se an — = — i : 
Lead... nee At —_ — — LOO + O18 
Alloy A ee eee 2-4) = = 98 + 0-40 
| Alloy B Re oat a O85 = 9915 + 0°60 
Alloy Ct wes aes O-4 O15 99°45 + 0°35 
Alloy Dt aa Seal — OD 0°25 99°25 + 0°74 
| 


* Taken as the range of stress which will cause failure after 10 million reversals. 
+ Attention is drawn to the fact that Alloys C and D come within the scope of the British Non-Ferrous 
Metals Research Association British Patent 272320. 


Alloy A is preferable to the other alloys for positions where organic acid corrosion occurs, e.g., ships’ 
holds. 

Alloy B is suitable for any position where vibration is serious and where an alloy stiffer than A and C 
ran be accepted. 

Alloy © is suitable where vibration resistance, combined with flexibility for installation purposes, is 
necessary. 

Alloy D is suitable for positions requiring a higher resistance to vibration than is given by the 
other alloys. 


Paper CaBLes.—With reference to paper and varnished-cambric insulated cables, they are similar 
in one respect, viz., the necessity for lead sheathing. Paper by itself is relatively a poor insulator, and 
its principal function in the cable is to mechanically locate and support the conductor. It is the oil 
with which it is impregnated which supplies the insulation properties. Consequently lead sheathing is 
essential to retain the oil and prevent evaporation, and the ends must be sealed for similar reasons. The 
seal consists of a box surrounding the end of the cable, which is filled with a suitable compound, Long 
vertical runs should be avoided, as the oil bleeds from the cable unless adequate precautions are taken. 
Paper cables are very little used in the United Kingdom, but are used more extensively on the Continent. 


They can be run at much higher temperatures than rubber, viz., 176° F. (80°C.), and the current 
‘atings are based on a temperature rise of 50°F. (27:7°C.), as compared with 20° F. for rubber. 
Consequently, for a given current a smaller section of conductor may be used, and for heavy currents, 
provided the voltage drop is not a limiting condition, considerable saving in cost will result, ‘in spite of 
the cost of sealing ends. 

The disadvantage of this type of cable is that, if a break should occur in the lead sheath, failure will 
sooner or later take place. 


20 


VARNISHED-CamBric CasLes.—In the United Kingdom and U.S8.A., extended use is being made 
of varnished-cambric insulated cables. The basis consists of cotton or linen cloth which is impregnated 
with a varnish, and dried. As in the case of paper insulation, the cambric is a poor insulator and merely 
acts a8 a mechanical support for the varnish, but whereas the oil in paper cables will evaporate if exposed 
to the air, the varnish is not so susceptible, and will maintain its electrical properties for much longer 
periods. 

The cambrie is made originally in wide sheets, say 40 inches in width, and after varnishing it is cut 
into tapes varying from about 4 inch to 1} inches in width, which are then wound on the conductor. 
It will be appreciated that cutting into tape in this fashion leaves two edges which are unvarnished, and 
the exposed ends of the threads will absorb moisture if left unprotected. It is therefore necessary to 
delay cutting until the rolls of tape are required for use, or alternatively, to wrap the rolls in grease paper 
and store them in dry situations. For these reasons also, varnished-cambric cables must be lead covered. 

in order to allow the layers of cambrie to slide easily without tearing or rucking when the cable,is 
bent, it is necessary to lubricate the layers by applying a small quantity of oil or petroleum jelly to the 
tapes prior to manufacturing the cable. Needless to say the tapes must be applied alternately left and 
right hand. 

These cables must also be sealed at the ends but not necessarily with compound as with paper. The 
sealing can be efficiently done with Waterproof tapes wound over the exposed ends and finally varnished, 
the arrangement being as shown in Fig. 5. 

Present ratings of varnished-cambrie cables are 90 per cent of the ratings for paper but it is probable 
in the near future these may be increased to the same values. Experience tends to show that they may 
be run at the same temperatures as paper. 


There are two types of varnished cambric, the one yellow in appearance which is produced from linseed 
oil and the other black produced from bitumen. The former if used direct on copper is inclined to set 
up a chemical action which is evidenced by a green deposit. It is, therefore, required that when yellow 
tape is used the conductors must be tinned or, alternatively, a paper or other suitable separator used 
under the first layer. 


SECTION 6—INSTALLING AND FIXING oF CABLES. 


SUPPORT AND PRorecrion or CaBLes.—The Rules are fairly explicit as to the methods to be 
employed but one point requires special emphasis. All cables must be securely fixed throughout their 
run, whether visible or concealed behind panelling. Loose bundles of wiring behind panelling should on 
no account be permitted. Particular attention should be paid to cables passing through decks, bulkheads 
and beams to see that no chafing or abrasion can occur due to the working of the vessel and these points 
should be specially examined during construction. These holes should invariably be bushed with lead or 
soft non-ferrous material as required by Section 6, clause 6. 


SEcTion 7—Main Disrripution. 


ContRoL or Circurrs.—Considerable doubt and difference of opinion exists as to the exact inter- 
pretation of Clauses 1 and 2 with reference to the provision of switches to control cireuits at distribution 
boards. 

If clause 1 (4) be carefully read in conjunction with clause 2 (a) one must inevitably come to the 
conclusion that every outgoing circuit from all intermediate switchboards or section boards is to be 
provided with a fuse on each insulated pole and a switch on one insulated pole. Only on the final 
sub-distribution board may the switch be omitted. Plans submitted for approval do not always indicate 
in detail what switchgear is to be supplied for these intermediate section boards, and it is, therefore, the 
duty of local Surveyors to see that these requirements are complied with. 

INTERFERENCE WITH MaGyeric Compass.—A case occurred recently which emphasises the necessity 
for secing that machines in the vicinity of the magnetic compass are in operation while compass 
adjustments are in progress. Serious errors were found in service which were not present during the 
trials, and they were traced to a motor converter used for wireless purposes. The radio had not been 
used during the trials, so the adverse effect on the compass was not detected. All the items referred to 
in clause 8, which are in close proximity to the compass, should be operated during these trials. 


?| 


SHORE CONNECTIONS :—Fuses or circuit breakers are now required to be fitted adjacent to the 
incoming shore connection terminals. It is sometimes argued that the shore supply will have overload 
protection at the shore distribution panel but this is not satisfactory from the point of view of any 
particular ship. The shore protection will be fixed in relation t» the shore feeders and plant and without 
regard to the compacity of the installation in any ship which may use them. Hence each ship must 
provide protection commensurate with the cables and busbars installed therein. In some cases it is 
possible and intended that current shall be supplied from ship to shore, or from ship to ship as in salvage 
operations, and then protection is necessary at the busbar end as well as the shore terminal end. 


Incidentally, it is perhaps well to stress the change of thought which has taken place on the general 
application of overload protection. In the early days, protection was based mainly on the idea of saving 
the apparatus connected to the cables. Now-a-days protection concentrates primarily on the cables, the 
apparatus, though not left entirely out of the picture, being of secondary consideration. 


Section 8—SEcONDARY BATTERIES FOR LIGHTING AND PowER. 

The danger of explosion due to insufficient or improper ventilation is not sufficiently realised and it 
applies equally to acid and alkatine batteries. During the gassing period while charging, hydrogen is given 
off which must be carried away by means of supply and exhaust ventilators. Dependence on ventilating 
fans for this purpose shonld be depreeated owing to the possibility of forgetting to start the fans or 
of the fans stopping due to failure of a fuse. 

. For similar reasons it is necessary to see that switches, fuses or other electrical fittings, liable to cause 
an are, are not placed in the battery room. Reversed current protection must invariably be fitted as 
required by the Rules, and fuses or other form of overload protection must be placed immediately outside 
the battery room. 


Section 9—Firvines. 

Switches and other fittings constructed of bakelite require to be carefully examined and tested to see 
that they are non-ignitable as specified in the Rules. Some forms of bakelite are highly inflammable. A 
simple rough and ready test is to take a sample and apply a match. A good quality of bakelite will be 
difficult to ignite even after the application of a second match while the sample is still hot and will be self- 
extinguishing in a few seconds. Whilst on this subject it might be as well to define the differences between 
various terms which are sometimes loosely applied. The term ‘tincombustible” is regarded as synonymous 
With “non-ignitable” and applies to a material which neither burns nor gives off inflammable vapours in 
sufficient quantity to ignite at a pilot flame when heated in a recognised manner. 

With reference to “non-inflammable” materials, various degrees of non-inflammability are recognised, 
such as “non-inflammable” * materials of very low inflammability” and “materials of low inflammability.” 
Briefly stated, the test consists in taking a sample 6 ins. (152°4 mm.) square and 4 in. (12°7 mm.) thick 
and supporting it under prescribed conditions at an angle of 45°. A flat-bottomed cup 2 in. diameter 
containing 0°3 c.c, of alcohol placed 1 in. below the centre of the specimen is then ignited and will burn 
for about 45 seconds. The grading of the specimens is based on the extent of the burning which takes 
place. In some cases a ragged hole is made in the centre of the specimen for a further test. 

Materials in which charring or scorching does not reach the edge of the under-face of the sample 
and which, when the perforated sheet is tested, do not continue to glow or carry flame after the spirit test 
flame has burned out, are *non-inflammable.” Materials which do not burn to such an extent that 
charring or scorching extends more than 2 ins. across the edge of the under surface and which, when a 
perforated sheet is tested, do not glow or burn for more than 15 seconds after the test flame has burned 
out are of “very low inflammability.” More extensive scorching or charring within certain defined 
limits, and burning for not more than 60 seconds, constitutes “low inflammability.” Complete details of 
these tests will be found in British Standard Specification 476. They are not primarily intended to be 
applied to the materials now under consideration but are quoted here as a matter of general interest and 
to illustrate the difference between “ non-ignitable” and * non-inflammable” and to point out that there 
are various degrees of non-inflammability. 

Attention is directed to the requirement that miniature lampholders are not to be fitted on systems 
exceeding 110 volts. A standard lamp cap is 2 in. diameter and fittings smaller than this are not to be 


f 


used on the higher voltage circuits. The small and miniature fittings are sometimes to be found in 
morse signal lamps and navigation light indicators and in berth lights. In this connection a morse 
lamp fitting having small fittings supplied by Messrs. Telford, Grier and Mackay & Co., Glasgow, has 
received the approval of the Committee for use on circuits in excess of 110 volts subject to the compliance 
with the following special requirements ;— 


1. The lamp fittings are to be mounted on a base of insulation of approved material, and all 
the drilled holes and machined surfaces in same are to be varnished after machining. 

2. A double pole switch is to be installed so that both poles may be isolated when replacing 
lamps or attending to maintenance. 

3. For pressures above 110 volts the lamps are to be connected in series or series parallel so 
that no individual lamp exceeds 110 volts, 


The objection to these small fittings is the very small clearances between live parts and the metal 
shroud and the very small terminals which are unsatisfactory for looping in. Even in full-size fittings the 
clearances are such that they are the most frequent cause of earths and electrical faults, 


Section 10—Heatine anp Cookin APPLIANCES, 

Electric radiators are perhaps respousible for more so called “electrical fires” than any other 
cause. Blankets and bed-linen, clothes and other inflammable objects are frequently left to dry in front of 
a radiator and they have been found in many cases to have fallen across the red hot elements with the 
inevitable consequences. It is for this reason that radiators are now required to be of the convector type 
in which the heaters are at “black heat” temperatures, except in suitable situations in public rooms. 
There are many suitable heaters of this type on the market and, if properly designed, are most efficient. 
The requirements do not prohibit the use of ordinary incandescent lamps for producing an artificial glow 
to simulate a coal fire effect. 


Portable appliances must be such that they cannot easily overturn and must have suitable positions 
provided for stowage purposes so that their movement may be constrained in heavy weather. It is also 
important that portable appliances should have the framework earthed by means of three-core flexible cords 
in which the third wire is connected to a point on the hull and to the frame of the appliance. 


Section 11—Morors. 


Much that has already been said about generators applies equally to motors, particularly with 
reference to methods to be employed when making temperature tests. 


In connection with variable speed motors where the speed is adjusted by shunt field control a point 
of special interest arises. The shunt field current is at the maximum value when the motor is running at 
the minimum speed, consequently the heating in the shunt winding is also at its maximum. In addition 
to this, the ventilating effect. with self-ventilated motors is also at a minimum at this speed. The heating 
in the main armature circuits is at its maximum at the high speed, the current usually being proportional 
to the speed, or in the case of centrifugal fans and pumps, proportional to the square of the speed. It is 
therefore necessary with variable speed motors to test them at top and bottom speeds; the armature, 
interpoles, commutator and series windings will reach their maximum temperature on the high speed and 
the shunt field will be at its maximum on the bottom speed. 


The practice in such cases should be to take the six hour heat run at maximum speed and after 
recording temperatures, run at least two hours at minimum speed to obtain shunt field temperatures. If 
there is a series of machines of identical design it will be sufficient if this be done on the first machine in 
order to check the design, subsequent machines being tested at the maximum speed only. If the makers 
consent it will be acceptable to combine these two tests by running the machine at minimum speed with 
armature currents corresponding to the load at top speed. In either case the test is to be followed by 
the overload test in the usual way. 


Another important point to observe when testing compound wound motors, either constant or 
variable speed, is what is known as a “rising characteristic.” This is characterised by an increase in 
speed with increase of load, the shunt field strength remaining constant. It will readily be appreciated 


23 


that, if an increase in load causes an increase in speed, a vicious cirele occurs. It may not be very 
appreciable at low loads, but may become unmanageable at full load and above. If the speed rise is very 
small it may possibly be nullified to some extent by the increase in potential drop in the supply cables as 
the load increases, and as it may not be detected during ship trials if the motor is not fully loaded, it is 
necessary to see that the motor is satisfactory by noting the results of shop tests. 


To guard against this condition, the speed characteristic must be such that, with the same value of 
shunt field current, the ‘no load” speed is higher than the “full load” speed. Test results should be 
scrutinised for this feature before they are accepted. 


The full series of tests to be taken on motors should be as follows :— 


(1) Speed characteristic, full load to no load. If it is a variable speed motor this should 
he taken at the top and bottom speeds. 


(2) Temperature tests. (Sve below.) 


(3) Commutation on overloads. (See below.) 
(4) Insulation resistance. 
(5) High voltage dielectric test between all windings and earth. 


The temperature tests should be as follows :— 
(L) Constanry SPEED Morors. 


(a) If tested by Hopkinson method, six hours (or until constant) on full load. Temperatures 
to be taken every half-hour on both machines, and maximum temperatures after shutting 
down to be recorded. Follow by 2 hours at 25 per cent overload on the motoring machine 
and again record temperatures on both machines. It will be noted that during the six hour run 
the generating machine will be under-loaded, but it will be approximately fully loaded during the 
25 per cent overload test. 

(6) If tested coupled to the driven apparatus, e.g., pumps or fan, test for 6 hours (or until 
constant) and record temperatures. Follow this by 2 hours at 25 per cent. overload unless the 
nature of the drive is such that overloads are impracticable. 


(2) VartasLE SpeeD Morors. 


(a) If tested by Hopkinson method, 6 hours (or until constant) at the maximum speed and 
after taking temperatures on both machines follow by 2 hours at minimum speed and again record 
temperatures. Follow this by 2 hours at 25 per cent. overload on the motoring machine at 
maximum speed. If duplicate motors are to be provided, the low speed test is required on the first 
machine only. 

(6) If tested with the driven apparatus take similar tests, omitting the overload test if over- 
loading is impracticable with the apparatus to which the motor is coupled. 


The commutation tests are to be taken at the overloads specified in Appendix 2, clause 4. If the 
load available is insufficient to obtain these overloads at normal voltage, the voltage may be reduced in 
order to obtain the required current. The main object is to see that commutation at the overload currents 
is satisfactory. With variable speed motors the overload factors need not be applied to the slow speed 
rating but are to be applied to the maximum speed rating. 


The question of staggering of brushes on the commutators of motors and generators should be included 
in the inspection. Very frequently it is found, especially where there is a comparatively wide space between 
adjacent brushes on the same arm, the staggering is insufficient to cover the gap. The Rule should be 
taken literally and observation made to see that there are no lanes between brushes which are not covered. 
It does not appear to be sufficiently appreciated that the maker’s test certificates for all motors for essential 
services are to be obtained from the shipbuilders at the shipbuilding port and attached to the official 
reports. The handling of reports is frequently delayed by omission to comply with this requirement. It 
has been necessitated by the fact that only by this means can any check be kept on manufacturers to see 
that they are aware of, and comply with, the requirements. 


24 


The same applies to generators. Until this Rule was instituted not only were manufacturers 
supplying motors and generators which, very often due to ignorance of the Rules, did not comply with 
the requirements but the Society had no means of ascertaining whether they complied or not. It is also 
essential these certificates be obtained at the earliest possible moment and checked immediately. 
Complications arise if this very necessary procedure is neglected and serious faults are found in the 
results after the ship has completed her trials and, in al! probability, left the builders’ hands. 


Section 12—Conrron Gear. 

Control gear as a general rule calls for little comment but, nevertheless, should be invariably 
examined individually. It is useless having a first class motor if the control gear is poor and shoddy or 
badly installed. Needless to say it should be splash proof and installed in readily accessible positions. 
There is a tendency to ignore the requirement that the ends of all cables having a sectional area of 
0-04 sq. in. and above are to be provided with soldering sockets. This rule, therefore, applies to all 
cables for 64 amps. (19/:052) or 25 sy. mm. and above, Solder should on no account be used for 
connections to resistances. 


Section 18—InTERNAL COMMUNICATIONS. 


The chief item calling for comment is the requirement that all apparatus is to be constructed to 
take the full pressure of the source of supply and if the pressure of supply exceeds 25 volts the whole of 
the installation is to be fitted in accordance with the requirements for lighting and power circuits. This 
means without question that if the communication circuits are in any way connected to the ship’s supply 
they must be fully insulated for the ship’s voltage. 

With reference to cables, some misapprehension exists in certain quarters, but it is quite clear from 
clause 4 that they must be insulated in the same manner as lighting and power cables, regardless of 
voltage. It is clearly stated they must be one of the types specified in Section 5, clause 1, i.e., either 
V.I.R., paper or varnished-cambri¢ insulated. 


SEcTion 15—Suips Carryinc PETROLEUM IN BULK. 


CaBLEs.—It should be made clear that the acceptance of * HR” type cables, in lieu of lead-sheathed 
cables for engine rooms, should not be extended to inelude tanker installations, unless the cables are 
installed in steel conduit. 

There is an additional reason for the requirement for a lead sheath on tanker cables, viz., for 
additional safety. The lead sheath in this instance, in addition to protecting the cable against oxidation. 
provides a continuous earthed metal sheath over the whole of the installation, and if failure of the 
dielectric occurs at any point, it can be detected immediately at the main switchboard. Without this 
sheath, the insulation might fail in a concealed position and remain undetected for a considerable length 
of time, eventually giving rise to a serious breakdown. 

Considerable difference of opinion exists as to the best method of fitting cables for the fore and aft 
run across the decks. Some owners prefer these cables to be run in pipes, while others will not tolerate 
this method under any circumstances. It is hoped the discussion on this paper will elicit further views 
and experiences on this vexed question. It is argued that in pipes it is difficult to remove a damaged 
cable which may lie under a number of other cables, also that condensation and possibly dangerous 
gases may collect. 

The alternative is to clip the cables in an exposed position on steel plates or channels. This enables 
the condition of the cables to be seen and cables can be easily renewed. It is claimed that although paint 
may be applied to protect the armouring, it is nevertheless ‘attacked by sea water, and corrosion takes 
place in way of the clips and at the parts which are inaccessible for painting. 

Whichever method is adopted, ample provision must be made for expansion. In the case of pipes, 
it is necessary they should be of ample cross section to enable the cables to be threaded in without 
damage, and to be easily removed for replacement in the event of failure. The total cross-sectional 
area of the cables should not be more than approximately 30 per cent of the internal area of the pipe. 
Substantial stuffing boxes with adjustable packed glands should be provided at intervals to allow for 


25 


expansion and the working of the ship. The open ends of the pipes should be carried through into 
spaces free of steam and other sources of ‘moisture and inflammable gases. The pipes should be 
galvanised inside and out and of substantial thickness. Following is a guide to suitable thicknesses :— 


TABLE VII. 
; in. : 
Nominal Bore | Thickness of | 

of Pipe. Pipe. 
Inches. | Inches. 
| j 0128 
| I | Orld4d4 
| 14 O16 
| 14 0176 

2 O'176 

24 to 6 0°192 


If the cables are clipped to channels the ends should not be rigidly attached to bulkheads at the 
poop, midship house and forecastle and suitable expansion bends or bights should be provided at these 
points. [t is also essential the cables, whether in pipes or otherwise, be kept at a suitable distance from 
steam or exhaust pipes and be free from any heating effect from these sources. At bulkheads where the 
heat is liable to be transferred by conduction, cables should not be within 18 inches of the flanges of 
steam pipes more than 3 ins. diameter and not less than 12 ins. from the flanges of pipes 8 ins. or less in 
diameter. 


Some engineers make a point of keeping negative cables in one pipe and positive in another. If one 
considers the matter in detail there does not appear any practical advantage in this. There is, however, 
a practical disadvantage, particularly in the neighbourhood of magnetic compasses. If the negative feed 
is in one steel pipe and the positive in another there is a definite electro-magnetic loop and with the 
increased use of electricity tending towards higher currents this may be a serious factor. 


HARTHING.—It is expressly stated that no part of the system is to be earthed but sanction is 
sometimes sought to use the single wire system with the hull as one pole. This cannot be permitted in 
any circumstances for obvious reasons. Apart from the risks of sparking involved in using the ship’s 
plates as conductors of electricity it has to be realised that every fault to earth on the insulated pole 
constitutes a direct short circuit. In a two-wire insulated system a fault on one pole will not cause any 
arcing though it must be immediately rectified lest an earth occur on the opposite pole. But with any 
part of the system earthed an accidental earth on any other part of the system of different potential will 
produce an are. 


For this reason earth indicating lamps invariably should be provided with switches so that normally 
they can be isolated and only used when the engineer in charge wishes to make a test. 


FLAME-PROOF APPARATUS—A good deal of misconception exists as to the safety of so-called gastight 
fittings and what constitutes a flame-proof enclosure and it is advisable to devote a little space to this 
subject. The official British Standard definition is as follows :— 


“A Flame-proof Bnelosure (including explosion proof) for electrical apparatus is one which will 
withstand, without injury, any explosion thal may occur in practice within it wnder the conditions 
of operation within the rating of the apparatus enclosed by it (and recognised overloads, if any, 
associated therewith) and wiil prevent the transmission of flame such as will ignite any inflammable 
mixture which may be present in the surrounding atmosphere.” 


26 


There can be no question of half-measures where flame-proof apparatus is concerned and if there is any 
risk of explosion in any situation it is only begging the question to prescribe “gastight” fittings. They 
are utterly useless in any atmosphere where there is the slightest risk of accummulations of gases of an 
explosive nature. Much valuable work has been done and knowledge gained in recent years as a result of 
research, foremost in this respect being the work carried on at Sheffield University, which for many years 
was the authority recognised by the Ministry of Mines for the issue of certificates for flame-proof apparatus. 
The issue of these certificates has now been taken over entirely by the Ministry of Mines, testing being 
carried out at their Buxton testing station. While the work of this station is primarily in connection 
with coal mines they will extend their certificates to cover other inflammable gases such as petrol but it 
is clear that an apparatus approved for coal mines may not necessarily be suitable for other conditions. 


It has been established that the gas producing the maximum internal pressure is a 9°5 per cent. 
methane-air mixture and this is the mixture used for testing. The maximum pressure produced is 110 Ibs 
per square in., provided it is ignited when at atmospheric pressure and the enclosed space is not sub-divided 
so as to form separate compartments in gaseous communication with one another. The substitution of 
hydrogen or of town gas, for methane does not increase the maximum pressure but the explosion is more 
rapidly developed and the flame difficult to stop. There are many other factors, such as turbulence of the 
gas, etc., which may worsen the results of explosion in electrical gear but space will not permit elaboration 
at this juncture. We must therefore be content with a general review of some of the salient points in 
relation to flame-proof enclosures. 


Short of permanent hermetic sealing, it must be assumed that any external explosive atmosphere 
may find its way eventually within the enclosure. In electrical apparatus heat is almost invariably 
generated, and repeated expansion and contraction of the air will cause breathing, and will draw in the 
explosive vapours. Moreover, an ignitable atmosphere may be produced within the enclosure by the 
decomposition of oils or varnishes, or insulating compounds such as bitumen or rubber. The term, 
‘“gastight enclosure,” therefore, has been deliberately and officially discarded in favour of the term 
** flame-proof enclosure.” 


The object aimed at when designing flame-proof enclosures, is to provide for release of the pressure 
generated by internal explosion, and to so direct the escaping gases that they are cooled to such an extent 
that the exterior gases are not ignited. It should be explained that the method of testing is to fill the 
enclosure with the most explosive mixture, surround it with a similar atmosphere, and ignite the 
enclosed gases by an electric spark. 


The escaping gases, in general, may be cooled either by allowing them to pass through the bolted 
flanges, suitably designed for the purpose, or by providing safety vents having labyrinth passages through 
which the gas passes. 


If flange protection is adopted, certain minimum requirements have been established. | Experiment 
has shown that a gap ;% (0°047) in. wide between rigidly spaced flanges 1 in. broad, forming a 
circumferential vent in spherical vessels ranging in capacity from 1 to 8 litres, will not pass the flame of 
a methane-air mixture, but that an increase in the gap width to ,\; (0°0625) in. resulted in an external 
explosion with flange breadths of 1 in., 14 ins. and 2 ins. As it is impossible, in practice, to ensure that 
a gap designed to be ; in. shall not at any time attain ,',, it has been laid down that for this, 
and other reasons, the gap should never exceed ,, (0°02 in.). The cooling of escaping gas may not 
depend solely on the abstraction of heat by contact with the metal surfaces, but may result from rapid 
expansion through an orifice. Cooling by expansion presupposes a high velocity in the escaping products 
of combustion, and this in turn depends upon the pressure developed. 


Rubber, asbestos, or any material which is liable to deteriorate, or is capable of disintegration, must 
not be used for the packing of joints. The surface of flange joints must have a breadth of not less than 
1 in., and the presence of bolt holes may be disregarded in this measurement provided the minimum 
distance between the inner edge of the bolt hole and the inner edge of the flange be 2 in. 


If removable bolts, studs or screws are provided for the attachment of component parts, the holes 
for the reception of such bolts, studs or screws must not pass through the walls of the enclosure, and the 
thickness of metal left at the bottom of the blind holes must not be less than } in., or one-third of the 
diameter of the hole, whichever is the greater. 


In the case of rotating parts, such as motor shafts and operating spindles, suitable precautions and 
principles have to be observed and terminal arrangements have to fulfil certain requirements. 


The foregoing covers but a fraction of the essential features but sufficient has been said to indicate 
that no ordinary total enclosure will fulfil the requirements of a flame-proof enclosure. It must be 
specially designed for the purpose and the design must undergo a rigid and almost microscopic 
examination of detail by people well versed in the requirements. One small opening or a screw which 
can be thoughtlessly left out may undo all the thought and care expended in more obvious directions. 


The Society’s Rules contain no reference to flame-proof enclosures but they are required in the case 
of certain canals and rivers such as the Aire and Calder, Manchester Ship Canal, Port of London 
Authority, certificates for which have to be issued by the Society. 


DANGEROUS Spaces.—The rules as at present framed refer specifically to lamps in certain situations 
but it should be understood that the restrictions applying to lamps apply equally to any other appliances. 


SecTIon 18—SparRE Gear. 


Certain types of electrical insulation are completely ruined and of no further use if allowed to 
become damp or saturated with oil and dirt. It is, therefore, of the utmost importance that spare gear 
he stowed in clean dry situations, protected from mechanical damage. Such parts as armatures and field 
coils, control gear coils and resistances (if they embody insulating material) should be tested to see that 
they are still serviceable. Certain spare gear is required to be carried on board, and should be inspected 
at the time of Periodical Surveys. 


CoNCLUSION. 


If colleagues have been sutticiently interested to read so far, the author is grateful and sufficiently 
rewarded for the time spent in preparing this paper, which he hopes will be of service in the interpretation 
and application of the somewhat voluminous rules on this subject. It will be apparent that many phases 
have heen left completely unmentioned, but it is hoped other colleagues, bearing in mind the injunctioa 
contained in the opening quotation, will come forward at some future date and elaborate one or other of 
the branches of this work. 


*LEMBERATURE. - _C:. 


40 


30 


20 


® SHUNT FIELD WINDING. 
@® SERIES Fi—ELD WINDING. 


@ INTERPOLE WINDING. 


Time - Hours 


FIG. 1. 
TyPicAL TEMPERATURE GRAPH OF A 200 Kw DYNAMO 


ALL SPOOL THERMOMETERS 


| FROM TOP 


FIG. 2. 


TYPICAL ILLUSTRATION OF A MOTOR OR DYNAMO WITH END SHIELD REMOVED TO SHOW 
PLACING OF THERMOMETERS FOR TEMPERATURE TEST. (See page 4.) 


Fi. 


Rt: 


@s) Stel eee 


FIGs 3: 


CONNECTIONS FOR HOPKINSON OR BACK-TO-BACK TEST OF TWO SIMILAR MACHINES 


COUPLED TOGETHER. 


Armature of machine acting as generator. 
Armature of machine acting as motor. 
Shunt field windings of the two machines. 
Regulating resistances. 

Ammeter measuring generator load. 
Ammeter measuring the input (losses), 
Ammeter measuring generator field current. 
Ammeter measuring motor field current. 
Voltmeter indicating machine voltage. 
Field switch. 


The two machines are belted or mechanically coupled together. 


ee 
MINIMUM 

UNOBSTRUCTED 

PASSAGEWAY. 


[| 
Teo t 


BE 


ay co 
dane BEC 
Vat “I 


/ 
) 3¢ Fig. 4 
TYPICAL 
ELEVATION 
mi OF 


5 
\ SWITCHBOARD 
\ 
| WITH FUSES 


E 
/ AT REAR 
a. oF PANEL. 


Oi Stix Tape To FiLt up 


To THE LeveL oF, LEAD COVERING. 


CABLE END SOLDERED 


Into SockeT. Proorep (Sticky) Tape. 


PrRooreD (Sticky) Tape LEAD CoveERING. 
TO BE KEPT CLEAR oF Socker. 


VARNISHED CAMBRIC 
STRANDED CoNnDucToR SoL_DERED INSULATION. 
UP SOLID. 
CaBle SockerT. 


Fig.S. MetHop oF SEALING VARNISHED CamBric CaBLeEs. 


On Att Sizes up To & INcLuDING °*25°% 


oa” 
Sketcn Suows °25 . Casre. 


DISCUSSION ON Mr. G. O. WATSON’S PAPER 


ON 


THE MANUFACTURE, SURVEY AND TESTING 
OF ELECTRICAL EQUIPMENT. 


R. C. Ciayron (Liverpool). 

I should like to congratulate Mr. Watson on giving us a most interesting and instructive 
paper, which has made clear a number of somewhat obscure points in the Rules and also given 
some very useful guidance in the observance of them, particularly in regard to the testing of 
generators and motors at the manufacturers’ works. I have felt that we have long been in need 
of a detailed interpretation of the Rules, to ensure that various differences of opinion as to their 
correct meaning should be brought on to a common basis. 

I would like to make some comments on the parts of the Rules covered by the paper, and 
also to raise some queries regarding other sections, and in doing so I am quoting section and 
paragraph of the Rules to save too many quotations. 

Section 4. General.—The author’s claim that the submission of plans is regarded as the 
most important and beneficial addition to the Rules of recent times is no understatement. 
It has helped considerably to have such things as switehboards and wiring correctly designed 
and ordered, and thus save the unpleasant necessity of having to have things altered in the 
last rush of getting a ship away on trials, even if this was possible. The mere fact that plans 
have to be properly prepared has made many firms realise that the electrical installations on 
ships are no longer to be considered merely as an unnecessary evil. 

The question of submission of plans for alterations or additions to existing installations is 
a much more difficult one. The usual procedure is for a vessel to come into port for a few 
days for some hull or engine repair, and while these are in hand it is found that the owners 
are installing a domestic refrigerating plant, floodlights on the masts, heaters in crew's quarters 
or altering passenger accommodation. The work is probably completed before it is found that 
anything is even contemplated, and seldom is any plan made. To help surveyors to ensure that 
plans are sent in for approval, a clause in the Rules pointing out clearly that these are required 
for alterations and additions would be most advantageous. 

Section 2. Generating Plant.—The information given regarding the mechanical and elee- 
trical tests to be carried out at a manufacturers’ works and the interpretation of the overloads 
in Appendix 2 are helpful. 

There are very few makers who fit thermometers to the stationary parts of machines 
during the temperature test, and this is only possible where the machine is of the open type. 
Where it is possible, it is usually to the makers’ advantage, however, as often the machine 
reaches a steady temperature under six hours. One manufacturer I know of tries to cut the 
actual time of test down to a minimum by running the machine for a short time on overload to 
bring the temperatures up quickly and then for a period on full load to allow the temperatures 
to become steady; this is the only method which will indicate that a satisfactory test has 
been made. 


2 


The explanation of compounding is most useful, as there are a number of people who do 
not appreciate that over-compounding is only an electrical method of overcoming a mechanical 
failing so as to ensure a constant voltage at the bus-bars. In this connection I have often 
found that when the machines have been fitted on the ship the brush setting, as marked at the 
shop tests, has not given the correct compounding even where speeds at N.L. ‘and F.L. have 
been exactly the same on the various generators. This is due to the different lengths of the 
equalizer cables and by slight adjustments of the brush setting a uniform compounding has 
been obtained. 


Section 3. Switchboards. Reversed Current Trips.—The protection which these give is 
essential on Diesel engine driven generators where fuel valves frequently give trouble, but while 
carrying out periodie surveys recently on two vessels twelve or more years old, I found that 
these trips did not and never could have worked, since they and the ammeters were wrongly 
connected. In each case the ammeter had been connected to the same pole as the equalizer 
and was thus giving quite an untrue indication of the load on each generator. Of course, this 
gave the impression that the machines were working very well in parallel as all the ammeters 
gave the same reading. 


Fusible Cut-outs.—The list of fuses which have been “approved” is very small and some 
indication as to the action to be taken by a Surveyor when fuses of other makes are put for- 
vard would be helpful. Unless this action is the same in all ports, little good can be done, but 
if all unapproved fuses were rejected the fuse makers would soon make some effort to obtain 
approval. There must be quite a number of good fuses, the makers of which are just waiting 
to be pushed to get them approved. 


Section 5. Insulation and Protective Covering of Cables.—The information contained in 
this part of the paper is very interesting. With regard to the use of plastic compounds for 
sealing cable ends, I have found quite a number of low insulation tests caused by the mis-use 
of sealing compounds. On investigation it has turned out that the electrician has applied the 
compound with damp hands or even spat on it to make it more plastic. If damp gets worked 
into the compound it is difficult to get rid of. 

H. R. Cables.—There seems to be some discrepancy in the thicknesses of dielectric and 
other coverings of the various approved makes, which causes one considerable worry in deciding 
whether they are satisfactory. A table giving the minimum thicknesses acceptable would be 
helpful. A possible reason for the discrepancies may be that the makers do not make increases 
in the thicknesses of coverings at exactly the same size of conductor. This variation in thick- 
ness also causes trouble with clips since a standard size cannot be kept to. 


Section 7. Main Distribution. Control of Circuits.—The Rule requirement that a S.P. switch 
in addition to D.P. fuses must be fitted to all outgoing circuits from intermediate and section 
boards is one, the carrying out of which leads to a considerable amount of opposition, due to 
three reasons: (a) cost; (b) lack of room; and (c) the opinion that very little added safety or 
usefulness is obtained. 

As far as the Society is concerned safety is the main idea behind all rules, and in my 
opinion this rule is one which could be with advantage modified, as in its present form it tends 
to inerease the doubtful practice of looping in at distribution boxes, i.e., feeding several distribu- 
tion boxes from one cireuit from ‘a section board. From observation it would appear that for 
moderately loaded circuits the switches are seldom used since being S.P. they do not isolate a 
cireuit and the fuses have to be drawn for testing and repairs. Where the load is not more 
than 20 amps. I think that elimination of the S.P. switch would tend to give a better arrange- 
ment of feeding distribution boxes without any reduction in safety and would tend to draw 
notice to the necessity of fitting the switch for circuits loaded above this suggested amperage. 

Section 15. Ships Carrying Petroleum in Bulk.—The information given on the subject of 
cables run fore and aft along the decks is both interesting and instructive. Except in vessels of 


the trunk type the cables have of necessity to be run along the gangway, and movement is un- 
avoidable. None of the methods so far used with L.C. or L.C. & A. eables seem to be ideal 
due to frequent cracking of the lead at the expansion points. In my opinion H.R, cable in pipe 
should offer a solution to this diffieulty and since the eables are much lighter than L.C. there 
is more chance of being able to draw out a defective cable. 

H.R. cable in pipe for masts would get over the troubles arising from hanging a long and 
heavy length of L.C. cable from one point at the top of the pipe. 

It has been common practice to run the cable pipes into the centre castle space and then 
clip the cables to tray leaving the pipe ends open. This might on the face of it allow the pipes 
to beeome filled with inflammable gas, but so far as I am aware no accident has occurred due to 
an explosion in these pipes. If the pipes are sealed at the ends they still cannot be considered 
gastight as breathing must take place at the expansion joints. Which is the better—to have 
fairly free ventilation through the pipes or to possibly get a pocket of gas into them? 

With regard to Dangerous Spaces there seems to be a tendency to use tube with inspection 
elbows and tees for the wiring, especially in the centre castle space. This type of tee and elbow 
allows the cable to be drawn in with less chance of damage to the lead than if these fittings 
were solid and if the covers are well fitted with jointing material there is no great risk of gas 
accumulating in the pipe. 

A point which always strikes me in regard to the centre castle space is the casual way it 
was dealt with in the older ships where ordinary tumbler switches, fuse boxes and cargo con- 
nection boxes were fitted indiscriminately without, so far as I am aware, any resulting accident. 
In our present day tankers there is usually an open stairway leading down from the aecom- 
modation with a wooden door at the stair head which, even when closed, would not prevent 
eas passing into the officers’ quarters. Often, too, the hospital is situated in this space. 

The necessity of fitting cartridge type fuses throughout a tanker seems rather superfluous, 
since they are mounted with ordinary D.P. knife switches on the main switchboard and in the 
vicinity of D.P. tumbler switches elsewhere. Dynamos, too, are of the open type, and in 
machinery spaces the boilers will always provide a ready means of igniting explosive gas. 
Remarks on points m the Rules, other than those covered by the Paper. 

Section 3. Par. 4 (a). Position of Switchbcards.—The wording of this paragraph is clear, 
but does not give sufficient emphasis to the common fault of running pipes for water, steam 
or other services in the vicinity of the switchboard. Where these pipes are run behind or over 
switchboards they should be free from flanges in way of the switehboard since, even if these 
do not leak, (as is always stated by engineers or plumbers) the fact that men may have to work 
on them with spanners is dangerous. It would be of great help if the rule could be strengthened 
to prohibit pipes being allowed in compartments provided specially for switehboards, or within 
specified distances of a switchboard placed in an open space. 

Section 3. Par. 2 (c).—There seems to be some confusion in regard to the correct way of 
connecting to a D.P. dynamo knife switch where there is more than one dynamo, these not 
being for parallel running, and where the outgoing cireuits are controlled by S8.P. throw over 
switches. It would seem that in this ease the dynamo should be connected to the knife blades 
and the bus bars (one leg of which will always be alive) connected to the switch jaws since if 
the switch is open it is probable the dynamo will be shut down. 

Section 3. Par. 7 (d), (e) and (g)—In these paragraphs various clearances between live 
metal and eases are given, but there is no indication as to whether these are direct clearances 
or creepage distances. There are few instances in which these clearances are met unless it is 
taken as creepage distance, this being particularly the case where fuses are of the so-called 
Home Office pattern with all live metal surrounded by porcelain or other insulating material. 

Section 6. Par.4 (d). Installing and Fixing of Cables.—The cutting back for half an inch 
of the tape from the end of the dielectric is a point which is sometimes neglected and which 
leads to considerable trouble in meeting the requirements of the Rules in regard to insulation 
resistance, especially at periodie surveys, due to the tape holding moisture. 


4 


Section 6. Par. 3. Support and Protection of Cables.—In paragraphs (b) and (h) it will be 
noticed that the resistance between any two points of the metallic envelopes of cables must not 
exceed two ohms, and yet in final sub-cireuits these metallic envelopes are to be earthed at the 
supply end only. Even when the cables are not for final sub-cireuits and are earthed at both ends it 
is probable that the resistance of fairly long lengths of lead and armouring can exceed two ohms 
and for the lead in an armoured eable or in a braided cable or the armouring where there is 
outer braiding present some difficulties if intermediate bonding is to be done. 


There is a further point raised in paragraph (1) which is often overlooked, especially 
where L.C. and braided cables are used for small wiring in accommodation where fittings are 
mounted on wood blocks, and that is ensuring the continuity of the lead sheath. The method 
adopted by some firms of fitting a shaped brass piece under the last clip at fittings or switches 
or in the wood blocks is not too satisfactory as the lead is sometimes broken. Another method 
is to remove the braid under the last clip at fittings and place a strip of lead under the elip. 
This is quite a neat method, but there is a considerable chance of the lead being eut through 
when taking off the braid. It would be helpful to know if any satisfactory solution has been 
made of this problem. 


I gather that there is some doubt as to whether earthing of cable coverings and continuity 
thereof is necessary for voltages under 150, but I will make a comment on this later. 


Paragraphs (e) and (f) dealing with refrigerating chambers, seem to be in need of revision 
as lead covered cables have now been very largely replaced by H.R. cables clipped with ordinary 
brass or galvanised iron clips. These deviations from the actual reading of the Rules have 
been approved in so many instances that it would appear some fresh ruling is now required. 

From personal observation I have found that in cold stores ashore L.C. cables are rapidly 
being replaced by rubber covered cables, usually C.T.S. mounted on porcelain cleats, which 
are giving very satisfactory service. 

The following method has been used in a number of ships :—H.R. cable clipped to wood 
grounds with brass clips, the cable, the wood grounds and the clips inside and out being coated 
with shellac varnish before installing. I have seen cases more than eight years old where 
the cables have been moved for repairs to insulation and then replaced, which are still quite 
satisfactory. 


Paragraph (e) states that cables passing through the insulation of refrigerating chambers 
are to be protected by a continuous lead tube flanged over at each end. It would usually be 
much more convenient to use a galvanised iron tube in place of the lead and the author’s 
remarks regarding this point would be of interest, it being noted that galvanised iron is now 
used very largely for casings, ete., in refrigerating chambers. 


Section 6. Par. 5. Watertight Glands and Deck Tubes.—There is a tendeney for deck 
tubes to be too short, the length being regulated by the height of coamings which, although it 
gives satisfaction to the Naval Architect, leaves a lot to be desired electrically. These tubes 
often protrude only about nine inches above a deck and some one to two inches from the 
bulkhead up which the eables are clipped, the result being a somewhat abrupt bend from the 
top of the tube to a clip on the bulkhead and where L.C. cable is used, there is a good chance of 
the lead cracking, due to relative movement of bulkhead and deck. If the deck tube is 
lengthened and bent to come against and be clipped to the bulkhead, this trouble can be very 
largely eliminated and where the cables are liable to damage, protection is afforded by the pipe. 


Section 10. Heating and Cooking Appliances. Par.2. Provision for Earthing.—A definite 
voltage of 150 is here given above which apparatus for these services is to be earthed. 
Why this limit of pressure for the earthing of galley gear and not for cable sheaths, motors and 
other apparatus much less likely to be handled when alive? Some explanation of what is 
required would help towards uniformity. 


5 


Section 14, Motors, and Section 12, Control Gear and Resistances.—In these two sections 
no mention is made regarding the method of control for motors. Where motors are fed through 
D.P. fuses and S.P. switches on a main or auxiliary switchboard and are controlled by a face- 
plate type starter on one pole only, it is necessary to draw the fuses to be sure the machine 
is “dead” as the S.P. switeh and the starter are not always in the opposite poles. Where 
motors are fed from a distribution box, there is often no switch in the final cireuit excepting 
the starter. D.P. switching at the main or distribution switehboard is much the most. satis- 
factory, but some explanation of the minimum acceptable switeh and control gear would be 
appreciated. 

In Section 11 definite mention is made regarding earthing of motor frames irrespective 
of supply pressure, but in Section 12 no mention at all is made regarding earthing of control 
gear and resistance cases. The necessity of earthing all metal cases is generally appreciated, 
but the facet that it is not mentioned here allows the wily a loophole for eseape. 

Section 148. Spare Gear. Insulator Tester.—It is recommended that for all equipments of 
100 kw. and above, irrespective of supply pressure, a 500 volt insulation tester be provided. The 
insulation testers provided by the Society for the use of Surveyors are also 500 volts and it is 
required that in periodie surveys, as laid down on pages 25 and 26 of the Rules, all machines, 
cireuits, ete., be tested for insulation resistance. Some comment has been made regarding the 
use of a 500 volt megger on installations with pressures of 110 volts or below, the opinion being 
that the test is excessively searching and that a 250 volt megger should be used, which even 
then would give a test voltage of over twice the working voltage. Can tests made with a 250 
volt megger (if available) be aecepted on a 110 volt installation? 

Conclusion.—I hope that these comments may be of help in showing some of the difficulties 
met with by the ordinary Surveyor in an outport in interpreting and carrying out the Rules. 

Mr. Watson’s reply to these and to the numerous comments on this excellent paper which, 
it is hoped, will be forthcoming from other Surveyors, is eagerly awaited. 


D. L. H. Couurson (Hull). 


Mr. Watson’s paper on the “Manufacture, Survey and Testing of Electrical Equipment” is 
very welcome and will prove a valuable addition to the Staff Association transactions, and a 
great help to those of his colleagues who are not gifted with his comprehensive and specialised 
knowledge of the subject. 

Referring to Section 1, Plans—I wonder if the author realises the difficulty that Surveyors 
have in obtaining plans for submission. We very often have to deal with comparatively small 
firms to whom the installation of a four or five kw. electric lighting set is only a very oceasional 
job sandwiched between many house installations. To obtain plans from such presents more 
difficulties than drawing the teeth of a man-eating tiger, and generally ends in the Surveyor 
making the plan himself. Even firms whose officials have some knowledge of the draughts- 
man’s art begrudge plans and regard their preparation as an unnecessary charge on a contract 
which has probably already been eut to the bone. 

I would ask if (in the case of these small installations) it could be arranged to make one 
plan sufficient, viz., the wiring of the switchboard. I enclose a blue print of a standard plan 
I drew up for a firm in this distriet. This plan, it will be seen, has blank spaces left for filling 
in the actual sizes of the cables, ete. Its.dimensions are exactly the same as the report form, 
so that if desired it can be filed flat with it. 

The Tables given in the paper are very valuable, especially Tables I, IV and V, giving lists 
of approved items. 

Might I suggest that the publication from time to time of additions to this list would be 
of considerable help and probably avoid correspondence. The small number of approved fuses 
and the absence of the names of some of the larger firms from the list is very surprising. 


6 


The author’s remarks in Section 15 regarding ships carrying petroleum in bulk are of 
particular interest to us in Hull, dealing as we do with a large number of petrol carrying 
barges trading on the Aire & Calder Navigation Waterways. 

I am very glad to see that he definitely states in the first paragraph that “gastight” fittings 
are utterly useless in any atmosphere where there is the slightest risk of aceumulation of gases 
of an explosive nature. I have for the past few vears been pointing out to barge owners in 
this district the desirability of fitting flame proof fittings in lieu of the so-called “gastight” 
fittings, which we are only entitled to ask for under the Aire & Calder Navigation Authorities 
Regulations. 


At the beginning of the Seetion the question of running cables in pipes is raised. The 
above Regulations require that all cable be run in gastight conduit, and although this conduit 
is reasonably gastight when first erected it does not long remain so. Condensation does form 
in the conduit and deterioration of the dielectric sets in, and it is possible that a short within a 
cireuit which had inconveniently “breathed” in an explosive mixture might have disastrous 
results. 

In my opinion, a good armoured cable with suitable connections such as are used in mines 
is much preferable. 


A. W. B. Epwarps (Hull). 

Mr. Watson’s present paper will be of great assistance in dealing with new electrical 
installations in future cases, and it is sincerely hoped an additional paper or papers will be 
fortheoming dealing as effectively with surveys of existing installations. 

It is the latter type, especially those installations previously ‘“unelassed” whieh cause 
most of our doubts and troubles these days. Old vessels still occasionally turn up for Special 
Survey with electric lighting sets which have never previously been surveyed, and the condition 
of such a plant, say in a Greek tramp 25 to 30 years old can better be imagined than deseribed. 
In a few cases the installation has been in such a condition that it has been deemed advisable 
to recommend “installation not to be used” rather than put the owner to the expense of com- 
plete refitting in a vessel approaching scrapping age. For general guidance in such cases 
perhaps the author would be good enough to suggest just how far compliance with the Rules 
should be insisted upon regarding sueh things as :— 

1. Switehboards with fuses or switches alive in “off” position. 

2. Switehboards where the fuses simply consist of a piece of wire twisted between 
two terminals. 

3. “Looped in” joints and repairs in cable runs (i.e., no Junction boxes). 

4. Open type lampholders in machinery spaces. 

5. Use of open element heaters in cabins. 

6. Vessels not previously fitted with navigation light indicators. 


Many of these items are “original sin” and most Superintendents are not very sympathetic 
towards alterations after many years of satisfactory service. 

Another type of survey we oceasionally get is the installation of lighting sets in small 
vessels previously lighted by oil lamps. Since many of these small sets are of only one-and- 
a-half to five kw. with switchboards about two feet square and are installed by jobbing wiremen, 
are all the plans mentioned on page (1) of the paper to be insisted upon in all cases? It often 
happens in these small conversion jobs that the owner buys a cheap secondhand dynamo and 
engine of unknown vintage from a serap dealer. What are the requirements in these cases? 
Similarly, unknown sets such are found when classing an unelassed vessel are merely required 
to be opened up and generally examined (see page 27 of the Rules). Is this acceptable for the 
above mentioned type of ease or are further tests of the engine and dynamo required? 


9 
‘ 


A further question arising from these conversions is who should sign the First Entry 
Report regarding compass interference? It has, on occasion, been necessary to advise rewinding 
of the dynamo armature at a Special Survey. In the ease of small lighting sets, is a high 
voltage test on the new windings expected or is a megger test acceptable? Anything but the 
latter is impossible when the repair is carried out in the usual small contractors’ “converted 
stable” type of workshop ! 


Coming now to the other extreme, i.e., the survey of eleetrie light and power installations 
in motor vessels, it has been noted in a number of the older vessels that the rubber insulation 
of the main conductors between generators and main switchboard is being converted into a 
soft, spongy, sticky condition by the oily vapour. Is local retaping and bonding considered an 
efficient repair for this? A wide variation, even in sister vessels, has been noted in the setting 
of overload cireuit breakers. What percentage overload setting does the author consider 
advisable? The method of testing reverse current trips mentioned in the paper is very 
satisfactory, and has revealed unsuspected defects in one very recent case. 

In conclusion, may one ask how much time, approximately, should be spent in holding 
electrical surveys in :— 

1. Small lighting installations of say 10 kw. 


2. Eleetrie light and power installations of about 300 kw. in motor cargo vessels of 


about 7,000 tons, assuming average conditions in each case. 


H. Harrner (Glasgow). 


In his interpretation of the Rules for Electrical Equipment, Mr. Watson has supplied us 
with an excellent guide which will be of great assistance to all responsible for carrying out tests 
at manufacturers’ works, and surveys of electrical installations in general. 


In dealing with electrical equipment produced, installed, or maintained by a very large 
number of firms in this district alone, one is faced with the problem of innumerable points 
which are continually raised. The number of alternative interpretations put forward are 
amazing and the writer is certain the author’s expositions will be weleomed by his colleagues, 
and enable them to give more definite rulings than was possible hitherto. 


Switchboards.—The lack of adequate room and suitable positions for main and auxiliary 
switchboards, constitutes a danger which is extremely difficult to make many appreciate. The 
general feeling among many of those responsible for the lay-out of engine-rooms and accom- 
modation appears to be that any odd corner is suitable to accommodate switehboards and little 
consideration is given to the possibility of exposure to condensation, heat, ete. In many cases, 
the backs are inaccessible; consequently, examination and cleaning of the connections and 
panels cannot be carried out with any degree of efficiency. 

The worst offenders in this respect are some of the shipbuilding firms who employ con- 
tractors to install equipment. These contractors in many eases have certain spaces allocated to 
them and panels have to be made to suit, and little or no notice is taken of their protests or 
suggestions of alternative arrangements. More co-operation is obviously indicated between the 
shipyards and contractors, not only in conneetion with switehboards, but in the whole question 
of electrical equipment. 

The author’s comments on earth testing are worthy of note. The usual method of indication 
is the provision of the lamps in series with mid point earthed. This system is crude, but 
appears to be the accepted method of electricians, no doubt more on the score of economy 
than efficiency. In carrying out periodical surveys, the writer has often seen lamps of different 
candle power in series, and in one case recently 100 watt and 15 watt lamps were fitted. The 
junior engineer in charge of the installation complained that the “earth” which appeared to 
him to be evident could not be located. 


8 


The best method is undoubtedly the provision of a meter calibrated in megohms as 
deseribed by the author, the readings obtained are reliable, and also more readily understood 
by persons with only an elementary knowledge of electrical matters. 


Fuses.—The list of approved fuses is surprisingly small. Fuses manufactured by many 
other well-known and reputable firms are constantly being fitted on classed vessels. Many of 
these firms advertise in the technical press and also issue advertising matter in which data is 
given and statements made that their products comply with British Standards Specifications 
and Home Office requirements and tests, which in effect are similar to the Society’s require- 
ments. Does the author suggest that all fuses other than those tested should not be accepted? 
If so, and as it is impracticable to carry out the prescribed tests after installation, it appears 
to the writer that considerable time must elapse before the Rules can be made effective, unless 
pressure is brought to bear on the firms who have not submitted their products for approval. 

Overfusing of circuits, and especially sub-cireuits, is probably the most frequent fault 
found at periodical surveys in the older type of vessels, mostly due to unauthorised persons 
renewing fuses and having no knowledge of fuse wire values, absence of fuse information, and 
even if this is provided little or no notice is taken. 

Fuse boxes are invariably fitted in positions accessible to all members of the crew. Ship- 
owners should be encouraged to specify strong boxes fitted with locks, and the keys placed in 
charge of the ship’s electrician or engineer in charge of the equipment. 

Secondary Batteries.—The author rightly stresses the danger of explosion due to improper 
ventilation. Provision of suitable spaces for batteries is extremely difficult on yachts and small 
coasting vessels. In yachts, favourite places are tunnel recesses or engine rooms, and due to 
the restricted space, special arrangements are necessary to ventilate and protect the battery. 

The fitting of batteries in small coasting vessels for the supplying of current for lighting 
purposes in port is becoming inereasingly popular. Unfortunately, owing to the small size of 
these vessels, no separate battery room ean be provided and part of the engine room has to be 
utilised to stow the accumulators. In such eases, the writer has insisted on a canopy being fitted, 
with two ventilators carried to the open air, and the switchboard placed in a position as far 
distant as possible from the batteries. A warning notice is also fitted, prohibiting smoking and 
the use of naked lights. 

The stowage of batteries in such places should be deprecated, but it is exceedingly difficult 
to provide alternative accommodation in small vessels. 

Heating and Cooking Appliances.—Many cases could be quoted of glaring examples of 
exposure to risk of fire found during surveys, due to the use of portable radiators. Owing to 
the variety of cheap radiators, obtainable from almost any general store or ironmonger, there 
is a tendency for ship’s officers and erews to augment the heating of their cabins. It is com- 
paratively easy to connect a radiator to the cireuit wiring by the simple operation of plugging 
in to portable light or fan sockets which are totally inadequate for the current required to 
operate such radiators; or in the absence of available plug points, by tapping the wiring and 
joining flexible or any odd piece of cable. 


As a result of complaints made regarding the use of such appliances and mutilation of 
cables, it is pleasing to note that owners’ representatives are realising the danger and a few 
have issued definite instructions that electric heating units are not to be installed by members 
of the crew. 


Ships Carrying Petroleum in Bulk.—With regard to fore and aft cable runs, the writer’s 
opinion is that lead covered, armoured and braided cables clamped between hardwood cleats 
and secured to the gangway as illustrated in the sketch, is the best method of fitting. Cables 
fitted in this manner are protected from mechanical and heavy weather damage by the gang- 
way and are accessible for examination and painting. A faulty cable may be renewed with a 
minimum of trouble and without disturbing the remainder. The cleats being of wood, corrosion 


9 


which usually takes place in way of metal clips, is eliminated. Provision for expansion and 
working of the ship is easily arranged at each end of the run. The cable entry at forecastle, 
midship and poop bulkheads is through glands, a separate gland for each cable. 


In the past, cables run in pipes have been considered by many owners to be the best method, 
in spite of heavy repair bills due to deterioration of cables and pipes, breaking of cast iron 
draw-in boxes, ete. Some owners still specify lead-eovered cables in pipes; this is considered 
bad practice, owing to electrolytic action taking place between the lead sheathing and the zine 
content of the galvanised pipe; also, damage may be done to the cable during the drawing-in 
process. 


If pipes are to be used, they should be of large diameter, with welded flanges; screwed 
tubing should be avoided, as corrosion takes place at the screwed ends. Draw-in boxes should 
be of welded steel, heavily galvanised and ample provision for expansion and draining allowed 
on the run. Cables should be lead covered and armoured, or, preferably, lead covered, 
armoured and braided. 


C. H. Krunérrer (Copenhagen). 


[ think that at least all the Engineer Surveyors shall be very much indebted to 
Mr. Watson for having presented this excellent paper, which really constitutes a long needed 
treatise on electrical engineering and leaves very little to be added as regards distinctness and 
details. 


A few remarks, more of a personal character, might possibly be of interest :— 


Section 2. Generating Plant.—Under this heading mention is made of the frame as gener- 
ally being satisfactory, which I think will readily be agreed to. I should, however, like to draw 
the author’s attention to a feature which is generally not disclosed at the trials in the makers’ 
shop, viz., vibrations. 


In this country, the frames of the larger generators are rolled from heavy steel plates and 
electric welded, and the motive power at the tests is supplied from an electromotor, which does 
not set up vibrations. But later, when combined with a Diesel engine, the impulses from the 
latter will set up vibrations in the frame, which may become rather serious in the ease the 
critical number of vibrations of the frame coincides with the number of impulses received per 
minute from the Diesel. 


In order to avoid surprises a loeal firm has introduced a sort of “vibration test.” A small 
electromotor with an unbalaneed flywheel is attached to the generator frame and by varying 
its speed within the limits specified by the Diesel manufacturer it is possible to tell beforehand 
whether the frame will vibrate or not. 


The extent to which the vibrations in the long run would affect the life of a generator is 
not known, but one ease, at least, has come to my knowledge in which the brush holder brackets 
broke, the effeet of the vibrations being similar to that of an eccentric commutator. 


The trouble may be remedied by reinforcing the frame or, what is better still, by stiffening 
the common bed plate and/or seating for the unit. 


Testing.—It is particularly interesting what the author says about testing generators and 
motors on page six, from which it will appear that the 25 per cent overload test may be limited 
to one hour, while the 50 per cent and 100 per cent tests may be completely omitted. 


With reference to the temperature reading, I suppose that the permanent attachment and 
repeated reading of the thermometers during the test will in practice meet with many diffi- 
culties owing to the more or less inaccessible design of the machines, particularly those of drip 
proof, ventilated type. 


10 


Fusible Cut-outs—The author is assuming that the significance of the word “approved” 
in the Rules has in this particular case escaped general notice, and it is therefore anticipated 
that Mr. Watson, having made the above statement, will for some time have a busy time in 
approving fusible cut-outs. It should, however, be remembered that long before the present 
Rules were adopted many different types of such cut-outs had been approved by loeal authorities 
and had proved to be satisfactory, so that the Surveyors might have thought that 
they were of an “approved type,” so much more as the Rules do not say that the cut-outs have 
to be “submitted for approval”—a slight distinction in the termination which might very well 
have caused the reader to hesitate before taking action. 


Section 45. Ships Carrying Petroleum in Bulk.—The question of fitting cables in the fore 
and aft across the decks in tankers is certainly one of considerable interest. In this country, 
the most frequently used method consists in fitting the cables on a flat steel plate alongside or 
underneath the gangway. The cables are laid in a flat layer, not too many (sometimes only a 
couple) under the same clip, and they are carefully and richly painted all over (also under the 
clips) and then, as a rule, protected against the action of the sea and sun by a steel covering 
plate. 


For this purpose, the bedding plate is flanged at the edges. It is advisable that the 
covering plates should be easily removable and not too heavy to handle, and provision should 
be made for draining water which might otherwise accumulate inside the box. This method 
has the advantage that the cables are easily controlled and attended to and ean easily be 
replaced in ease of breakdown. 


Within the bridge space, which may in some eases be a “dangerous space,” it has become 
practice in this country to run the cables in what may be termed “gastight” steel casing. 
Apropos “gastight.” The lamps in the pump-rooms, ete., are to be contained in gastight 
. ° . ° . I . . - bi 
fittings, and as this apparently is a very problematic notion it occurs to me that the use of such 
fittings might as well be subject to approval as that of the fusible cut-outs. 
ta) 


The type of lamps generally employed in this country is an ineandescent lamp contained 
in a glass globe, the latter being packed on the lamp fittings by means of a rubber ring and 
a number of bolts and protected against damage by heavy wire grids. The wiring is enclosed 
in gastight tubing, carried into the lamp fitting, and in this connection it should be borne in 
mind that the enclosure eventually might “breathe” through the tubing and thus avoid drawing 
in gases. 


In conclusion, I should like to congratulate Mr. Watson with his excellent and instructive 
paper, which no doubt will be the subjeet of much discussion and eall for much comment on 
the part of the absent members of the staff. 


R. IL. Murcutson (Glasgow). 


Mr. Watson’s paper fills a specific need. The Staff Association has been looking forward to 
it with interest and many will read it with advantage. 


There are numerous points in the Rules whieh Surveyors, and particularly the younger 
Surveyors like myself, must at one time or another wish to have amplified. Manufaeturing 
methods change, and a man not in touch with the latest practice might interpret the Rules quite 
differently from one conversant with modern ideas. Uniform interpretation must make the 
application of the Rules easier. 


I can add very little to this comprehensive paper. In the manufacture and testing of 
generators and motors the makers know the Society’s requirements fairly well, and it is rare 
for machines to have to be rejected. One point, however, on which manufacturers and makers 


11 


are occasionally at fault is in insufficient clearance distance between live parts and earthed 
metal. The makers do not always foresee the possibility of clearances being reduced by foreign 
matter, or by movement of the parts concerned so that faults develop. With regard to switch- 
gear, it is found that some manufacturers fail to appreciate the effects of vibration, and in 
addition to absence of locking devices they do not provide adequate support or anchorage for the 
smaller connections. This may result in breakdown, either from chafing of insulation or from 
fracture of the connection. 


In conelusion I should like to congratulate the author on his excellent paper which, 
if I might suggest it, could be worthily followed by a similar paper dealing with the survey 
of existing installations, 


L. H. F. Youna (London). 


The author realises that a difficulty exists in interpreting the Rule for overeompounding of 
generators; and even the elucidation at the bottom of page five requires some thinking over. 
Looking at the question another way, the current-pressure characteristic for an ordinary com- 
pound wound dynamo is approximately a horizontal curve. By increasing the turns in the 
series coil the machine becomes overeompounded, which gives a rising curve, the purpose of 
this being to maintain a constant voltage at the far end of the external cireuit. 


The author might be asked to confirm that this is the intention of the Rule. It would 
seem that the only way in which the Surveyor could ascertain whether the dynamo were over- 
compounded would be to witness the machine running at different loads and then to examine the 
form of the characteristic curve. 


On page 14, the author refers to the size of conductors being related to the “diversity 
factor.” This is an important matter where essential services are coneerned, and the author 
appears to be well aware of this; but the reference to standby or duplicate pumps might lead 
to some ambiguity. If such pumps were for lubricating oil or cooling water or other services 
even connected with the main engines, some allowance might be made in the size of the cables, 
but if the term “standby” or “duplicate” refers to bilge or ballast pumps then the various 
cables should be up to full requirements, so that all these pumps could be worked at full 
capacity in case of emergency. 


Whilst on this subject, it might be noted that the Rules do not lay down any standard 
regarding the number of generators that should be installed in a vessel. In most eases the 
owners and builders give proper attention to this, particularly in large vessels. It is not merely 
a question of capacity, but of number of units. The Rules require a vessel to have at least 
two bilge pumps, two feed pumps in the case of steamships and two lubrieating oil pumps in 
the case of motor-vessels. Therefore, it is only reasonable to provide at least two generators 
where the above auxiliaries are electrically driven. 


The remarks on secondary batteries on page 21 are important. Most of the requirements 
‘an easily be met except in the case of yachts, where the batteries are often placed in the engine 
room. It is hardly practicable to arrange the battery in a gastight box with independent venti- 
lation, and, failing this, little more ean be done that depend on the engineer exercising due 
precaution when charging up. 


The author sets out the advantages and disadvantages of the various methods of running 
cables fore and aft in tankers. Builders and owners have their individual ideas about this. 
or easy maintenance it is generally considered preferable to have the cables exposed, there 
being little risk of damage as there would be in the ease of a vessel where general cargo is 


handled. 


12 


REPLY BY THE AUTHOR. 


Mr. R. C. Cuayron.—The mere length of the contribution from my confrére in Liverpool 
is to some extent a measure of the keen interest and conscientious manner in which he invari- 
ably approaches this subject, and I must thank him for his valuable contribution, to which I 
will reply under corresponding headings. 


Section 4. General.—The submission of plans for additions and alterations is admittedly 
a difficult subject—diffieult for one reason, because a definite line cannot be drawn between 
important and unimportant alterations. The addition of a lighting fitting or a switch by a 
competent electrician who knows what he is about calls for no inspection, but if carried out 
with festoons of flex by a steward in a storeroom then it becomes a serious matter. Such an 
installation would be instantly condemned on a new vessel, so why let it go unchecked at a 
later date? It is these alterations and also the addition of consuming devices which often 
overload existing cables and apparatus and constitute a grave risk. When additions are neces- 
sary even competent electrical engineers are frequently tempted to run risks which ordinarily 
they would shun, and the fact that the scheme has to be submitted for scrutiny by experts will 
often deter a man from exposing his foul intention to certain condemnation. 


Where the extensions are of a simple nature and can be deseribed in the Report in a simple 
manner it is perhaps asking a little too much to request plans, but the Surveyor should satisfy 
himself that the existing switchgear and eables will not be overloaded. Where the alterations 
are more extensive it is obviously necessary for the reasons stated by Mr. Clayton with 
reference to new installations for the electrical contractor to prepare some sort of scheme, and 
there can be no objection to submitting it for approval. The work can proceed in the 
meantime. 


Section 3. Switchboards. Reversed Current Trips. Mr. Clayton’s experience raises some 
pertinent points :— 


(a) The wrong connection he mentions is occasionally found on plans, again illus- 
trating the usefulness these serve. 


(b) What sort of survey did they get when built and on the occasion of the first and 
second periodical survey. 


Fusible Cutouts.—The first stage in the campaign for better fuses must be the extension of 
the approved list. It is steadily growing and more attention to the rejection of unapproved 
types will bring this matter to a head. The proper course is for Surveyors to point out that 
in future they cannot accept the unapproved makes. 


Section 5. Insulation and Protective Covering of Cables. H.R. Cables.—A new table em- 
bodying the correct diameters is being drawn up and will be issued in due course. 


Section 7. Main Distribution. Control of Circuits.—Mr. Clayton’s suggestions are very 
valuable and will be given due consideration. The clauses dealing with this point are couched 
in exceedingly complicated language and are difficult even for experts to interpret. This matter 
is receiving consideration with a view to simplification of the wording and classifying the whole 
position. 

Section 45. Ships Carrying Petroleum in Bulk.—The suggestion with reference to H.R. 
cable in pipe for masts is important. With reference to the sealing of pipes on fore and aft 
runs it is better to lead the ends into safe spaces and leave them open so that air can circulate 
freely. 


With reference to cartridge fuses, there are several reasons why they are to be preferred, 
reasons by the way, which apply not only to tankers but to all classes of vessel and an exten- 
sion of their use more generally is desirable. 


fund 
oo 


In the first place the are is extinguished by the powder in the cartridge and does not reach 
the outer atmosphere and no conducting vapours or ares are expelled which might cause short 
cireuit on to other adjacent conductors. Extensive tests have proved conclusively that they are 
the safest and most dependable fuse made and that under severe short cireuit the semi-enclosed 
rewireable fuse is not 100 per cent reliable. Secondly, they are calibrated and generally 
speaking it is not possible to insert a larger fuse than that for which the holder is designed, or 
if this should be done, it is done consciously and is easily detected by a Surveyor. They are 
not rogue-proof, but if an engineer wants a fire there are more ways of making one than over- 
fusing. Over-fusing is potentially an act of sabotage and should be treated as such. 


The fact that dynamos and boiler fires are of the open type is rather beside the point. The 
fuses protect cables leading to other parts of the vessel and they should be protected by the 
best available type of cutout. Furthermore, it is preferable to have one type throughout than to 
attempt to differentiate. For instance, if one allowed ordinary fuses in the engine room the 
anomoly would arise that a fuse in an alleyway would be of the cartridge type and on the 
other side of the easing, probably adjacent to the E.R. entrance door it could be a semi enclosed 
fuse. 

Replying to the remaining points, the question of pipe flanges near switehboards is 
important and will be kept in mind, but one does not want to introduce too many or too rigid 
regulations. It is better that Surveyors should exercise their persuasive powers and a hint 
dropped to an owner’s superintendent will often do the trick. The rule requires that the 
switchboards “are not exposed ... to damage from water, steam or oil” and that should be 
sufficient authority to object to the presence of flanges in positions where a leak would be 
dangerous. 


With regard to the connection of dynamo switches the case cited is not very common, but 
technically there is no very strong argument either way and no objection need be raised to 
either method, the solution suggested by Mr. Clayton being, perhaps, preferred. 


The clearances specified in Section 3, par. 7 (d), (e) and (g) may be taken as creepage 
distances. 


The cutting back of braiding, ete., for half an inch at the ends of cables is important and 
colleagues at other ports will do well to note Mr. Clayton’s remarks. I have recently 
encountered the practice of cutting back three or four inches and slipping a sleeve of “sistoflex,” 
a flexible varnished tube over the ends, and this is said to make an appreciable difference to the 
insulation resistance of the system. It is, however, a method which is open to criticism and is 
at the moment still under consideration as to whether it should be permitted, as ‘“‘sistoflex” is 
highly inflammable. 


It can be taken as fairly certain that in the comparatively short runs in ships the 
resistance of the lead sheath will rarely exceed two ohms from any point to the nearest end, even 
in final subeireuits. Therefore, there should be no difficulty in meeting the requirements if 
the earth connection is good. 

The reason for any doubts about earthing lead sheathing and armouring of cables, regard- 
less of voltage, is not apparent since Section 6, par. 3 (h) distinctly says, “Every lead-covered 
cable” and among the reasons are to combat electrolytic corrosion and to prevent interference 
with radio and direction finding. 


Mr. Clayton’s comments on cables in refrigerating chambers are very useful, and it would 
be interesting to have corresponding experiences from other districts. With reference to the 
requirement of a continuous lead tube for cables passing through insulation of refrigerating 
chambers, this is an example of rule drafting which illustrates the point that rules should 
preferably prescribe the principle to be observed rather than a particular method. Galvanised 
steel tubes are equally suitable and the principle involved is that the thermal insulation is to 
be sealed and protected. 


14 


The question of deck tubes is important and is one for the Surveyors and cannot be 
legislated for in Rules except in a general fashion. 

The regulations for earthing of heating and cooking appliances, motors, ete., are dictated 
by considerations of safety from shock, ete. 

The switching of motor circuits requires clearing up in future consideration of the Rules, 
it being noted that I.E.E. Regulation 102 requires a switch on each insulated pole, in addition 
to the fuses or cireuit breaker protecting the cireuit. 

With regard to the use of a 500 volt megger on 110 volt cireuits, I am of opinion that 
its employment is logical. In the first place the small meggers supplied to Surveyors do not 
maintain 500 volts if the leakage is excessive, as the small generator fitted to these becomes 
overloaded. Furthermore, generators and motors when new are subject to a test with A.C, of 
twice the working voltage plus 1,000, with a minimum of 2.000 for all above 3 kw., which means 
a peak voltage of 2,800. Therefore, it is not unreasonable to expect them to stand 500 volts 
D.C. With regard to other apparatus, any well-designed fitting will stand at least 1,000 volts 
D.C. when new, and the same argument applies. 


Mr. D. L. H. Cottiwson.—The difficulties with regard to plans are noted and I ean only 
reiterate the statement in the original paper, where the importance of these is emphasised and 
refer also to Mr. Clayton’s comments and the reply. No engineer would dream of constructing 
an engine without plans, and they are just as necessary to the electrician. If the installation 
is small the plans will be simple and quickly drawn up. Provided the essential circuits are 
shown as on the well-thought-out specimen submitted by Mr. Collinson, only one plan is 
necessary. The only comment on the plan is that the field regulator would have been better shown 
connected to a shunt terminal and it should be stated that the generator is compound wound 
in order to save an inevitable query when the plan is dealt with in London. 


The issue of an official cireular giving a list of approved fuses, H.R. cables and insulating 
materials is under consideration. 


Mr. A. W. B. Epwarps.—The points raised with reference to very old ships are important 
and worthy of individual treatment. 

(1) Switchboard with fuses or switches alive in “off” position. The requirement is one 
rather of safety to personnel and convenience of maintenance and does not vitally affect either 
reliability or safety of the installation and discretion may safely be exercised when dealing 
with such cases. 

(2) Switchboards where fuses simply consist of a piece of wire twisted between two 
terminals. It was precisely to deal with this class of fuse which must be dead when being renewed 
that the rule requiring them to be dead was introduced. They are unsatisfactory from all 
points of view and owners should be persuaded to replace them with modern types. 


(3) Looped in joints and repairs in cable runs (i.e., no junction boxes). Provided a joint 
be made on orthodox lines by a competent cable jointer, the strands being neatly ar ‘anged with 
plenty of overlap and properly sweated and taped up there is no doubt a satisfactory joint 
or tee can be made, but they should be thoroughly examined, the tape being removed for this 
purpose before acceptance. When re-taped new material should be used, the old tape being 
scrapped. 

(4) Open type lampholders in machinery spaces. A lot depends on the position and type 
of engine room. In motor ships they should be enclosed unless in some remote corner away 
from oily vapour. In steamships a little more latitude might be allowed, but in the vicinity of 
the engine they should be enclosed. ‘An instance is on record of a fire having been caused by 
an escape of hot oil impinging on an open type lamp from which the well elass had been 
removed. 

(5) Use of open element heaters in cabins. The requirements for heaters were added to 
the rules fairly recently and are not retrospective. 


15 


(6) Vessels not previously fitted with navigation light indicators. This omission does not 
render the installation unsafe from an electrical point of view, but the owner is legally respon- 
sible for maintaining navigating lights burning. The fitting of indieators is not a legal require- 
ment, but they give warning in the event of a failure of the lights which might otherwise be 
unnoticed, at any rate at the instant of failure, and it is therefore in the interests of the 
owner to fit them. 


With reference to the equipment of vessels previously unelassed, it is not feasible to 
apply tests to dynamos which would be applied normally to new machines, but they should be 
run under working conditions and generally put through a very striet survey in accordance 
with Special Survey requirements. Generators should be run on full load, the governor gear, 
compounding, parallel running tried, and all important engine room motors, windlass, steering 
gear, ete., run on load. 


No high voltage test is laid down for a rewind, and in many repair shops facilities do not 
exist and a megger test must therefore be accepted. 


The question of main conductors between generators and main switehboards being converted 
to a soft, spongy, sticky mess simply shows that the rules were not observed in the original 
installation, and it is hoped colleagues will note this comment. If the cables are lead covered 
as required by the Rules for cables in engine rooms, this would not happen. 


The overload setting depends on whether time delays are fitted and their nature. Generally 
speaking, 25 per cent overload setting with time lag devices and 50 per cent with instantaneous 
trips should meet most cases. 


With regard to time required for electrical surveys, everything depends on the nature of 
the installation and how it has been kept. A 10 kw. lighting installation should be completed 
in about two hours. A 300 kw. power and lighting installation in average condition should be 
completed comfortably in one day, but may occasionally take longer. It may be necessary to 
make a second visit if any repairs are recommended on the first visit. The Survey fees are 
a rough guide as to what has been allowed for. 


Mr. H. Harrner.—Lack of space for switchboards and dynamos is an old sore; it is a 
thing the average naval architect always remembers to forget. In the ease of one superinten- 
dent, who certainly did not come within this category, he insisted that the electrician should 
have first choice of position for all cable runs, and the plumbers and pipe workers had second 
choice—a very logical and sensible arrangement. 


In the matter of fitting meters to give a direct reading in megohms, the Continent is ahead 
of British firms, for whereas the latter rarely do it, it is very common practice abroad. 


Ample ventilation of battery spaces, particularly in yachts, is a problem which does not 
receive sufficient attention. In a certain yacht two mysterious explosions have occurred and 
although the evidence is incomplete it is fairly certain the engineer was examining them with a 
lighted pipe in his mouth. In another case recently, a man lit a match to see if the battery 
was gassing. Unfortunately for it him it was and he lost an eye. It is not sufficiently appre- 
ciated that hydrogen gas in given off by both acid and alkaline batteries. The impression 
seems to be that the ventilation requirement is purely to protect metal parts from acid fumes, 
but that is not so. With very small batteries in well-ventilated engine rooms the risk is small, 
but it is difficult to lay down any general rule and Surveyors must be guided by their own 
judgment. 


The fore and aft cable runs on tankers, as hinted in the paper, are the subject of much 
controversy, and Mr. Haffner’s suggestions are important. On the principle that one learns 
most from mistakes and failures, full details with sketches where necessary of cable failures in 
the fore and aft run in tankers will be much appreciated. 


16 


Mr. C. H. Krunorrer.—The reference to welded frames being affected by vibration from 
Diesel engines is interesting and unusual. With alternators one might expect this phenomena 
as the frame is usually very light as it does not form part of the magnetic cireuit. With 
D.C. machines the frame is part of the magnetic cireuit and, further, it has to be of ample 
section to reduce sagging and ovality due to the weight of the field coils and pole pieces, ete. 
Also any vibration set up in the frame would have to be transmitted through the bedplate. 

Breaking of the brush holder brackets is an entirely different matter, having nothing to do 
with the use of welded frame. If, as is very common on the Continent, the brush gear is 
mounted on the pedestal bearing it will be subject to shocks transmitted through the shaft and 
bedplate to the pedestal. The clearance in the bearings affects this matter and the impulses 
transmitted through the shaft may cause movement of the commutator, similar to that of 
eccentricity referred to by Mr. Kruhoffer, the forces being transmitted to the brush gear 
through the brushes and brush springs. 

With regard to Fusible Cut-outs, the London staff will no doubt be capable of dealing 
effectively with the stampede for approval, but in the meantime it would appear that my 
colleague’s country does not produce fuses and uses only those on the approved list. 

When inspecting “gastight” fittings on tankers it is not a bad plan to take hold of each 
protecting glass and give it a shake. I came across a vessel fitting out in a certain yard 
recently in which none of the clamp rings gripped the rubber ring and the glass was quite 
loose—anything but gastight. The contractor was as surprised as my colleague, but both had 
looked at the fitting and taken it for granted. 

Mr. R. I. Murcutson.—The suggestion of a paper dealing with the survey of existing 
electrical installations deserves further consideration and volunteers for such a paper for next 
session will no doubt be suitably acknowledged by the Hon. See. 

Mr. L. H. IF’. Younec.—With reference to compounding, the deseription in the paper might 
be amplified. The ordinary shunt wound machine, self excited, will have a drooping charac- 
teristic, i.e., as the load increases the voltage at the terminals falls. This is an inherent 
characteristic of the machine and the volts at full load will be 15 to 20 per cent less than at no 
load depending on the size and type of machine, but in addition to this electrical characteristic, 
a similar characteristic in the prime mover causes the speed to drop as the load increases, 
resulting in a further drop in volts. By adding series turns to the main poles both of these 
tendencies can be compensated for. It is convenient when generators are tested at the maker’s 
works to test them at constant speed, and if the series coils merely corrected the volts to the 
same value at full load, as at no load, there would still be a drop in volts proportional to the 
engine speeds when coupled to the prime mover. ‘Therefore, the Rule calls for a five per cent 
increase in volts at full load to compensate for this fall in speed which may be from two-and-a- 
half to five per cent. An alternative has recently been added to the Rule permitting level 
compounding when tested with the engine, i.e., the volts at no load and at full load to be equal. 

In land practice where the feeders to the consumer’s premises may be very long and result 
in a drop in pressure at the far end, it is common practice to provide for a five per cent 
increase in volts at the station busbars, but in ships where the feeders are not of such great 
length there is no necessity to make this provision. Excessive fall in pressure at the lamps and 
motors is taken care of by Section 4, par. 4. 

On the subject of “diversity factor” the reference to standby or duplicate services was 
meant to apply only to those which would never under any cireumstances be required to run 
simultaneously. For instance, it is common practice to connect the windlass to a cargo winch 
distribution board. In that case the supply cable to the distribution board is proportioned on 
what is estimated to be the maximum working load. 

A rule dealing with the number of generators to be installed is under consideration, Some 
opposition may arise, but it is, as Mr. Young infers, futile to require certain services to be 
duplicated when there is only one source of power. 


Navicarion Su6 Bonro 


S.P Switches & bP Fuses 


Each Lame Seragarenr WikEO 


& Fitte oO Wire lNorcator CiRcuIT 


Enoine Room 


Casre AmPs 


ENGine ROOM 


= ; : 


ACCOROOATION 


aa Ez E 


Pe Sa 


+—@ 


Switch Bonanno Pane eae 
Busneo Wirn ee 2] 


Sus Circurrs 


Carco Arr Eee " 


BP Linked Swircy 


ALL Sua Giacuyts FitteD Witn 
SP Sw tones & OP Fuses 


ELecTRIcAL INSTALLATION 


ILLUSTRATING D. L. H. 


COLLINSON’S 


(CONTRIBUTION. 


— Ross Seton Te? Gear ~ 


— Gears SPaceo AaouT 
=AERTS SPACE ABOUT 
12° AeaRT — 
AL wy 


— PLAN View — 


— MeTHOO OF Sécveinc CReles 
UNDER FoRE & AFT GANGWAY — 


ILLUSTRATING HH, HArrNer’s ConTRIBUTION. 


1 
Sreel Piare 


Jor & Borrort 


ales L.A ER. 


THICK. 


Lloyd’s Register Staff Association. 


ANNUAL MEETING. 


The Annual Business Meeting of the Staff Association was 
held in the London Office on Wednesday, 
24th March, 1937. 


Mr. G. D. Ritchie, the President, occupied the Chair. 

Apologies for absence received from Mr. W. Watt and Dr. B. C. Laws were intimated to the 
Meeting. 

The Minutes of the previous Annual Meeting, being already in the hands of the Meeting, were 
taken as read, and were adopted. 

The Hon. Secretary then submitted the financial statement, and stated that the estimated balance 
on the year’s working was £11, compared with £10 12s. 9d. for the previous year; Mr. S. T. Bryden 
moved and Mr. J. R. Clark seconded that the statement of accounts be adopted. 

Mr. Ritchie : It is customary for the President to make a few remarks at this meeting on the work 
of the past session. J think we can take it we have had a very satisfactory session. Attendances were 
good, and the papers that we had were very valuable, and fully in keeping with the traditions of the 
Association. The subjects covered a very wide field, and two of them—by Mr. J. G. Buchanan and 
Mr. G. Buchanan—were particularly opportune because their subjects were very prominently in the 
minds of everybody at the time. Valuable contributions were also given by Mr. G. O. Watson and 
Mr. G. T. Champness. 

The discussions as far as our meetings were concerned were entirely satisfactory, but I am not 
sure that the contributions of the outports were as good as might be desired. 

From the figures supplied by Mr. Murray, I find that in the 1935-86 session, 12 London Members, 
6 at home ports, and 5 at foreign ports took part. During the last session the corresponding figures 
were London 28, home ports 12, foreign ports 7. In the course of closer investigation I find, however, 
that the contributions from Glasgow, Liverpool and Newcastle were a good deal less numerous than from 
the other outports, and I would suggest to the senior men at these important centres that they should be 
a good deal more eager to give the Association the benefit of their wide experience. 

As showing the appreciation of the Association’s activities in far distant places, we have a letter 
from Mr. J. E. Alfaro, of Talcahuano, who records his indebtedness to the papers read. 

When this Association was in its earlier stages it was the practice at some of the outports for the 
staff to meet and discuss the papers. That: most estimable habit seems to have died out, but 1 suggest 
to my colleagues in the outports that they should resurrect that practice, and so give wider scope and 
interest to the papers and the Association generally. 

[ would like to take the opportunity of saying how much we appreciate the intervention of the 
younger members. You will remember Sir George Higgins, at the Annual Dinner a week or two back, 
made some cogent remarks on the young Surveyors having the benefit of the experience of the older 
men ; they should have no diffidence in asking questions at the meetings or asking the individual senior 


» 


men for their opinion on various matters. The senior mar will generally thoroughly enjoy himself in 
giving his opinion to a young colleague. If these young men ask their questions at an Association 
meeting, and do not feel that they want their remarks to appear in print, I am sure Mr. Murray 
will “edit” with discretion. : 


During the last session also we paid some visits to various places of interest—the Fuel Research 
Station at Greenwich ; the “ Vietory ” and the “Nelson” at Portsmouth (that was a mixed excursion to 
which we took our women-folk); then there was a very interesting visit to Callender’s Cable Works. We 
got this through the efforts of Mr. Heck, and it was a very enjoyable and instructive visit indeed. It is 
intended to continue these visits, and a trip to Woolwich Arsenal has been arranged. 


I will not detain you any longer except to say we have already a full syllabus for nest session. We 
are in the happy position of being favoured in October with a special lecture by Lord Essendon. We do 
not yet know what aspect of shipping he will deal with, but with such an authority it is certain to be a 
memorable occasion. 


The provisional syllabus is as follows :— 


1937. 
7TH OCTOBER % aoe ee Special Lecture. 
LorpD EssENDON. 
47H NOVEMBER x? a Fe “Remarks on Shipyard Practice.” 
A. W. JACKSON. 
2ND DECEMBER uh .w w “ Welding Developments in Germany.” 
R. B, SHEPHEARD. 
1938. 
3RD JANUARY nee ‘f ee “Vibration in Ships.” 
M. ConsTaNTINI. 
3rD MARCH ... 3 tt A> “ Refrigeration.” 


D. GEMMELL. 


So far, we have not secured a paper on an engineering subject, and J put it to my engineering colleagues 
that it is an opportunity to give a paper on recent developments in engineering. Mr. Watson tells me 
there should be no difficulty in getting a further paper on an electrical subject. 


Before I sit down I would like to refer to our late colleague and friend, Mr. Lockney. Mr. Lockney 
was a very keen member of this Association. He was a member of the Committee, ae at the time he 
severed his connection with the Society he was engaged in writing a paper for the Association. I 
think it is fitting we should refer to him at this time. 


I see from the Agenda that the next item to occupy your attention is the election of a President. 


Mr. Heck: For the high office of President of this Association I venture to put before you the 
name of a very old friend of mine. I am quite aware that the fact that he is a very old friend of mine 
may not commend itself to you, but when I also tell you that he is a very good friend of yours | am sure 
you will agree with me that the nomination of Mr. Ritchie is one that will meet with general approval. 


I think it can be said that Mr. Ritchie has carried out the duties of President with entire acceptance 
to all of us, with enthusiasm and with ability, and therefore with entire confidence I propose 
Mr. Ritchie be re-elected. 


Mr. T. R. H. Morrison: It gives me great pleasure to second the motion so ably proposed by 
Mr. Heek. : 


Mr. Ritchie accepted re-election. 


3 


Mr. Ritchie: The next item is the re-election of our Secretary. I am very happy to see 
Mr. Murray is prepared to carry on this office, and I think I should tell you how very fortunate I consider 
myself to be in having Mr. Murray as Secretary. If is no sinecure, and Mr. Murray has carried out his 
duties with great ability and enthusiasm in a very nice way. [ am greatly indebted to him, and I take 
the opportunity of saying how much his work has been appreciated. 


Mr. McAfee then proposed, and Mr, Lloyd Roberts seconded, that Mr. J. M. Murray should be 
re-elected Secretary, which was agreed to by the meeting. 


Mr. Murray: I shall have much pleasure in carrying on for another year. 


I should like to take this opportunity of mentioning how grateful I am to Mr. Kastaway, who does 
all the typing incidental to the job, and to Mr. Stevens and Mr. Cook, who, at considerable inconvenience 
to themselves, take shorthand notes of the discussions. 


ELECTION OF COMMITTEE. 


The London Members of the Committee were then elected as follows :—J. Anderson, G. A. Laing, 
C. H. Stocks, A. Urwin, R. J. L. Ward, G. O. Watson and L. H. F. Young. 


Mr. Blockside : Before we make our departure I would like, to move that our very best thanks be 
conveyed to Mr. Ritchie, our President. His breezy personality has kept us very much alive, and one 
feature and one result of his office during the past twelve months has been the increased interest in the 
discussions amongst the members of the London staff. On your behalf 1 offer to him our very best 
thanks for his work and interest and help. We look forward with a great deal of pleasure to the coming 
twelve months of his office. 


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